It looks like you are not familiar with these stuff. Normally people access android with limited set of access. So if users do something which Android thinks will cause problem with phone operation then android will block user for doing such changes. It's like UAC in windows vista or later.
Rooting is like giving Root access in linux PC or Administrator access in Windows PC. You can do whatever you want with your phone android will not prevent you. It will give you access to android system file access. SO Unless you want to bear some headache my advice is to stay away from rooting as there are hundreds of thing which can go wrong. :k
And rahul bro pointed out some points but there are few more disadvantages like there are some useful apps(like banking or apps like Tatasky everywhere) which may refused to work if you root phone. And few more advantages like Installing Xposed framework which can change the way how your phone and it's buttons work and pretty much everything on a phone