Newer browsers protect you better against viruses, scams and other threats. Outdated browsers have security holes which are fixed in updates
Speed
Every new browser generation improves speed
Compatibility & new Technology
You can view sites that are using the latest technology
Comfort & better experience
Have a more comfortable experience with new features, extensions and better customisability
I can't update my browser
If you can't change your browser because of compatibility issues, think about installing a second browser for browsing and keep the old onefor compatibility
Ask your admin to update your browser if you cannot install updates yourself