diff --git a/.github/workflows/codespell.yml b/.github/workflows/codespell.yml
index 05e5593f..e9222f63 100644
--- a/.github/workflows/codespell.yml
+++ b/.github/workflows/codespell.yml
@@ -1,6 +1,9 @@
 name: Codespell
 
 on:
+  push:
+    branches:
+      - '**'
   pull_request:
     types: [opened, synchronize, reopened, ready_for_review]
 
diff --git a/scripts/pi-hole/js/footer.js b/scripts/pi-hole/js/footer.js
index be54e1c1..bddadaa5 100644
--- a/scripts/pi-hole/js/footer.js
+++ b/scripts/pi-hole/js/footer.js
@@ -12,6 +12,24 @@
 
 var settingsLevel = 0;
 
+const REFRESH_INTERVAL = {
+  logs: 500, // 0.5 sec (logs page)
+  summary: 1000, // 1 sec (dashboard)
+  blocking: 10000, // 10 sec (all pages, sidebar)
+  metrics: 10000, // 10 sec (settings page)
+  system: 20000, // 20 sec (all pages, sidebar)
+  sensors: 20000, // 20 sec (all pages, sidebar)
+  query_types: 60000, // 1 min (dashboard)
+  upstreams: 60000, // 1 min (dashboard)
+  top_lists: 60000, // 1 min (dashboard)
+  messages: 60000, // 1 min (all pages)
+  version: 120000, // 2 min (all pages, footer)
+  ftl: 120000, // 2 min (all pages, sidebar)
+  hosts: 120000, // 2 min (settings page)
+  history: 600000, // 10 min (dashboard)
+  clients: 600000, // 10 min (dashboard)
+};
+
 function secondsTimeSpanToHMS(s) {
   var h = Math.floor(s / 3600); //Get whole hours
   s -= h * 3600;
@@ -86,17 +104,23 @@ function countDown() {
 }
 
 function checkBlocking() {
+  // Skip if page is hidden
+  if (document.hidden) {
+    utils.setTimer(checkBlocking, REFRESH_INTERVAL.blocking);
+    return;
+  }
+
   $.ajax({
     url: "/api/dns/blocking",
     method: "GET",
   })
     .done(function (data) {
       piholeChanged(data.blocking);
-      setTimeout(checkBlocking, 10000);
+      utils.setTimer(checkBlocking, REFRESH_INTERVAL.blocking);
     })
     .fail(function (data) {
       apiFailure(data);
-      setTimeout(checkBlocking, 30000);
+      utils.setTimer(checkBlocking, 3 * REFRESH_INTERVAL.blocking);
     });
 }
 
@@ -241,9 +265,8 @@ function updateFtlInfo() {
         ftl.allow_destructive ? "" : "Destructive actions are disabled by a config setting"
       );
 
-      // Update every 120 seconds
       clearTimeout(ftlinfoTimer);
-      ftlinfoTimer = setTimeout(updateFtlInfo, 120000);
+      ftlinfoTimer = utils.setTimer(updateFtlInfo, REFRESH_INTERVAL.ftl);
     })
     .fail(function (data) {
       apiFailure(data);
@@ -340,9 +363,9 @@ function updateSystemInfo() {
         moment.duration(1000 * system.uptime).humanize() + " (running since " + startdate + ")"
       );
       $("#sysinfo-system-overlay").hide();
-      // Update every 20 seconds
+
       clearTimeout(systemTimer);
-      systemTimer = setTimeout(updateSystemInfo, 20000);
+      systemTimer = utils.setTimer(updateSystemInfo, REFRESH_INTERVAL.system);
     })
     .fail(function (data) {
       apiFailure(data);
@@ -395,7 +418,7 @@ function updateSensorsInfo() {
 
       // Update every 20 seconds
       clearTimeout(sensorsTimer);
-      sensorsTimer = setTimeout(updateSensorsInfo, 20000);
+      sensorsTimer = utils.setTimer(updateSensorsInfo, REFRESH_INTERVAL.sensors);
     })
     .fail(function (data) {
       apiFailure(data);
@@ -564,9 +587,8 @@ function updateVersionInfo() {
         'To install updates, run <code><a href="https://docs.pi-hole.net/main/update/" rel="noopener" target="_blank">pihole -up</a></code>.'
       );
 
-    // Update every 120 seconds
     clearTimeout(versionTimer);
-    versionTimer = setTimeout(updateVersionInfo, 120000);
+    versionTimer = utils.setTimer(updateVersionInfo, REFRESH_INTERVAL.version);
   });
 }
 
@@ -589,8 +611,8 @@ $(function () {
   if (window.location.pathname !== "/admin/login") {
     // Run check immediately after page loading ...
     utils.checkMessages();
-    // ... and once again with five seconds delay
-    setTimeout(utils.checkMessages, 5000);
+    // ... and then periodically
+    utils.setInter(utils.checkMessages, REFRESH_INTERVAL.messages);
   }
 });
 
diff --git a/scripts/pi-hole/js/index.js b/scripts/pi-hole/js/index.js
index 03371648..160f89f0 100644
--- a/scripts/pi-hole/js/index.js
+++ b/scripts/pi-hole/js/index.js
@@ -5,7 +5,7 @@
  *  This file is copyright under the latest version of the EUPL.
  *  Please see LICENSE file for your rights under this license. */
 
-/* global utils:false, Chart:false, apiFailure:false, THEME_COLORS:false, customTooltips:false, htmlLegendPlugin:false,doughnutTooltip:false, ChartDeferred:false */
+/* global utils:false, Chart:false, apiFailure:false, THEME_COLORS:false, customTooltips:false, htmlLegendPlugin:false,doughnutTooltip:false, ChartDeferred:false, REFRESH_INTERVAL: false */
 
 // Define global variables
 var timeLineChart, clientsChart;
@@ -71,16 +71,14 @@ function updateQueriesOverTime() {
     timeLineChart.update();
   })
     .done(function () {
-      // Reload graph after 10 minutes
       failures = 0;
-      setTimeout(updateQueriesOverTime, 600000);
+      utils.setTimer(updateQueriesOverTime, REFRESH_INTERVAL.history);
     })
     .fail(function () {
       failures++;
       if (failures < 5) {
-        // Try again after 1 minute only if this has not failed more
-        // than five times in a row
-        setTimeout(updateQueriesOverTime, 60000);
+        // Try again ´only if this has not failed more than five times in a row
+        utils.setTimer(updateQueriesOverTime, 0.1 * REFRESH_INTERVAL.history);
       }
     })
     .fail(function (data) {
@@ -123,8 +121,7 @@ function updateQueryTypesPie() {
     queryTypePieChart.update("none");
   })
     .done(function () {
-      // Reload graph after minute
-      setTimeout(updateQueryTypesPie, 60000);
+      utils.setTimer(updateQueryTypesPie, REFRESH_INTERVAL.query_types);
     })
     .fail(function (data) {
       apiFailure(data);
@@ -185,14 +182,13 @@ function updateClientsOverTime() {
     .done(function () {
       // Reload graph after 10 minutes
       failures = 0;
-      setTimeout(updateClientsOverTime, 600000);
+      utils.setTimer(updateClientsOverTime, REFRESH_INTERVAL.clients);
     })
     .fail(function () {
       failures++;
       if (failures < 5) {
-        // Try again after 1 minute only if this has not failed more
-        // than five times in a row
-        setTimeout(updateClientsOverTime, 60000);
+        // Try again only if this has not failed more than five times in a row
+        utils.setTimer(updateClientsOverTime, 0.1 * REFRESH_INTERVAL.clients);
       }
     })
     .fail(function (data) {
@@ -253,8 +249,7 @@ function updateForwardDestinationsPie() {
     forwardDestinationPieChart.update("none");
   })
     .done(function () {
-      // Reload graph after one minute
-      setTimeout(updateForwardDestinationsPie, 60000);
+      utils.setTimer(updateForwardDestinationsPie, REFRESH_INTERVAL.upstreams);
     })
     .fail(function (data) {
       apiFailure(data);
@@ -382,7 +377,7 @@ function updateTopLists() {
   updateTopClientsTable(false);
 
   // Update top lists data every 10 seconds
-  setTimeout(updateTopLists, 10000);
+  utils.setTimer(updateTopLists, REFRESH_INTERVAL.top_lists);
 }
 
 function glowIfChanged(elem, textData) {
@@ -392,13 +387,7 @@ function glowIfChanged(elem, textData) {
   }
 }
 
-function updateSummaryData(runOnce) {
-  var setTimer = function (timeInSeconds) {
-    if (!runOnce) {
-      setTimeout(updateSummaryData, timeInSeconds * 1000);
-    }
-  };
-
+function updateSummaryData(runOnce = false) {
   $.getJSON("/api/stats/summary", function (data) {
     var intl = new Intl.NumberFormat();
     glowIfChanged($("span#dns_queries"), intl.format(parseInt(data.queries.total, 10)));
@@ -422,10 +411,10 @@ function updateSummaryData(runOnce) {
     }, 500);
   })
     .done(function () {
-      setTimer(1);
+      if (!runOnce) utils.setTimer(updateSummaryData, REFRESH_INTERVAL.summary);
     })
     .fail(function (data) {
-      setTimer(300);
+      utils.setTimer(updateSummaryData, 3 * REFRESH_INTERVAL.summary);
       apiFailure(data);
     });
 }
diff --git a/scripts/pi-hole/js/settings-system.js b/scripts/pi-hole/js/settings-system.js
index 4a0844f4..5bbe4e1a 100644
--- a/scripts/pi-hole/js/settings-system.js
+++ b/scripts/pi-hole/js/settings-system.js
@@ -5,7 +5,7 @@
  *  This file is copyright under the latest version of the EUPL.
  *  Please see LICENSE file for your rights under this license. */
 
-/* global apiFailure:false, Chart:false, THEME_COLORS:false, customTooltips:false, htmlLegendPlugin:false,doughnutTooltip:false, ChartDeferred:false */
+/* global apiFailure:false, Chart:false, THEME_COLORS:false, customTooltips:false, htmlLegendPlugin:false,doughnutTooltip:false, ChartDeferred:false, REFRESH_INTERVAL: false, utils: false */
 
 var hostinfoTimer = null;
 var cachePieChart = null;
@@ -105,9 +105,8 @@ function updateHostInfo() {
           " " +
           uname.machine
       );
-      // Update every 120 seconds
       clearTimeout(hostinfoTimer);
-      hostinfoTimer = setTimeout(updateHostInfo, 120000);
+      hostinfoTimer = utils.setTimer(updateHostInfo, REFRESH_INTERVAL.hosts);
     })
     .fail(function (data) {
       apiFailure(data);
@@ -173,9 +172,8 @@ function updateMetrics() {
       );
 
       $("div[id^='sysinfo-metrics-overlay']").hide();
-      // Update every 10 seconds
       clearTimeout(metricsTimer);
-      metricsTimer = setTimeout(updateMetrics, 10000);
+      metricsTimer = utils.setTimer(updateMetrics, REFRESH_INTERVAL.metrics);
     })
     .fail(function (data) {
       apiFailure(data);
diff --git a/scripts/pi-hole/js/taillog.js b/scripts/pi-hole/js/taillog.js
index 935cd9cd..486cc321 100644
--- a/scripts/pi-hole/js/taillog.js
+++ b/scripts/pi-hole/js/taillog.js
@@ -5,14 +5,11 @@
  *  This file is copyright under the latest version of the EUPL.
  *  Please see LICENSE file for your rights under this license. */
 
-/* global moment: false, apiFailure: false, utils: false */
+/* global moment: false, apiFailure: false, utils: false, REFRESH_INTERVAL: false */
 
 var nextID = 0;
 var lastPID = -1;
 
-// Check every 0.5s for fresh data
-const interval = 500;
-
 // Maximum number of lines to display
 const maxlines = 5000;
 
@@ -26,7 +23,7 @@ const markUpdates = true;
 function getData() {
   // Only update when spinner is spinning
   if (!$("#feed-icon").hasClass("fa-play")) {
-    window.setTimeout(getData, interval);
+    utils.setTimer(getData, REFRESH_INTERVAL.logs);
     return;
   }
 
@@ -63,7 +60,7 @@ function getData() {
           $("#output").html("<i>*** Log file is empty ***</i>");
         }
 
-        window.setTimeout(getData, interval);
+        utils.setTimer(getData, REFRESH_INTERVAL.logs);
         return;
       }
 
@@ -107,11 +104,11 @@ function getData() {
       // Set filename
       $("#filename").text(data.file);
 
-      window.setTimeout(getData, interval);
+      utils.setTimer(getData, REFRESH_INTERVAL.logs);
     })
     .fail(function (data) {
       apiFailure(data);
-      window.setTimeout(getData, 5 * interval);
+      utils.setTimer(getData, 5 * REFRESH_INTERVAL.logs);
     });
 }
 
diff --git a/scripts/pi-hole/js/utils.js b/scripts/pi-hole/js/utils.js
index 3e1b8af7..4d893111 100644
--- a/scripts/pi-hole/js/utils.js
+++ b/scripts/pi-hole/js/utils.js
@@ -616,6 +616,42 @@ function listAlert(type, items, data) {
   );
 }
 
+// Function that calls a function only if the page is currently visible. This is
+// useful to prevent unnecessary API calls when the page is not visible (e.g.
+// when the user is on another tab).
+function callIfVisible(func) {
+  if (document.hidden) {
+    // Page is not visible, try again in 1 second
+    window.setTimeout(callIfVisible, 1000, func);
+    return;
+  }
+
+  // Page is visible, call function instead
+  func();
+}
+
+// Timer that calls a function after <interval> milliseconds but only if the
+// page is currently visible. We cancel possibly running timers for the same
+// function before starting a new one to prevent multiple timers running at
+// the same time causing unnecessary identical API calls when the page is
+// visible again.
+function setTimer(func, interval) {
+  // Cancel possibly running timer
+  window.clearTimeout(func.timer);
+  // Start new timer
+  func.timer = window.setTimeout(callIfVisible, interval, func);
+}
+
+// Same as setTimer() but calls the function every <interval> milliseconds
+function setInter(func, interval) {
+  // Cancel possibly running timer
+  window.clearTimeout(func.timer);
+  // Start new timer
+  func.timer = window.setTimeout(callIfVisible, interval, func);
+  // Restart timer
+  window.setTimeout(setInter, interval, func, interval);
+}
+
 window.utils = (function () {
   return {
     escapeHtml: escapeHtml,
@@ -649,5 +685,7 @@ window.utils = (function () {
     hexEncode: hexEncode,
     hexDecode: hexDecode,
     listsAlert: listAlert,
+    setTimer: setTimer,
+    setInter: setInter,
   };
 })();