Updated at: Feb 18, 2022
You will become vulnerable to security problems
The primary reason for updating your web browser is to stay protected against security problems.
Web browsers are very complex pieces of software, and there are many things that can - and do - go wrong with them. If it's a bug where something "doesn't work right" then that's frustrating... but if the bug is something to do with security, then that's a huge problem.
Web browsers with unpatched security bugs can lead to viruses/malware being installed automatically and your personal information being stolen. These two things can then lead to even worse problems - if viruses or malware gets installed on your computer, then that malware can open your computer up to criminals who can then do all sorts of nasty things to you and your information - from stealing bank details, breaking in to your email and social media, sabotaging your work, and deleting your personal files.
The best way to prevent bugs in your web browser leading to serious vulnerabilities is to keep your browser up to date. Fortunately these days it's not hard to do.
Websites may not work properly
If there is a bug in your web browser that stops something working on a website, the website maker may try to implement a "work-around" so that copies of your out of date and broken web browser still work on their site.
But the easier solution is for you to just update your web browser. That way if there's a bug in your browser which is causing problems, the new version hopefully gets rid of it, and you're back to using the internet without problems.
You will miss out on new features
The number of things that websites are able to do now is always increasing. When the internet first launched, having animated images and scrolling text was ground-breaking. Now, we take things like high-resolution videos, live chat, full video games, and 3D graphics in our web browsers for granted and it's all thanks to our web browsers supporting more and more new features.
When new technology standards make something new possible on the internet, your web browser needs to be updated so that it is able to use those new features.
What's the worst that could happen if I don't update my browser?
A website not working properly is annoying, but it's not the worst thing that could happen with an out of date browser...
The worst case scenario I can think of would be that a malicious website finds away to automatically install dangerous software - a virus or malware - on your computer, without you even having to do anything. In otherwords, you don't even need to be tricked into downloading and running a program, instead the mere act of viewing a website (or an ad embedded in a website) is enough to load dangerous software on to your computer.
Often what happens in those scenarios is that the malicious software that gets installed automatically is then used to download more malicious software at the lesuire of the criminals who control it. And that's the software that does the real damage - stealing bank details, activating your web cam, stealing private photos and data, deleting your data, or encrypting it and holding you ransom for its safe return.
All of these things have happened in the past - on out of date browsers - and it's a very good reason to make sure your web browser is always up to date.
