This might sound like generic troubleshooting advice, but taking these steps does genuinely help to prevent issues with timeout.
Important things to note:
Depending on the type of browser you are using, the instructions might be slightly different. If you aren't sure how to check this, you can visit https://www.whatsmybrowser.org/ for help.
Getting Started with Internet Explorer:
Click on the gear wheel in the top right corner.
Click on Safety in the menu.
Click on Delete browsing history in the sub-menu.
Select Temporary Internet files and website files from the list.
Click on Delete.
On the bottom of the page the browser notifies you when the browser cache is cleared.
To perform a "Hard refresh" press the following key combination: Ctrl + F5
Getting Started with Google Chrome:
Click on the three dashes or three dots in the top right corner.
Click on More tools in the menu.
Click on Clear browsing data... in the menu on the left.
Select Cached images and files from the list.
Click on Clear data on the bottom. Your browser cache is now empty.
To perform a "Hard refresh" press the following key combination: Shift + Ctrl + F5
Getting Started with Mozilla Firefox:
Click on the orange Firefox button in the top left corner.
Move the mouse to Options and click on Options in the sub-menu.
Click on Advanced.
Click on the Network tab.
Click on Clear Now in the Cached Web Content section.
Getting Started with Safari:
Click on the ALT-key, when the menu bar on top of the screen isn't visible.
Click on Edit in the menu bar.
Click on Empty Cache... in the menu.
Click on Empty in the pop-up box.
To perform a "Hard refresh" press the following key combination: CMD + R