Average Lifespan of iPhone Home Button?

Personally, I have been using Assistive Touch since I first got my 4S, so I don't really use the Home Button at all.

I just wanted to know what the lifespan of it is for people who do use it. Because I don't really like Assistive Touch and wanna use the Home Button, but I am afraid it will break(I know it's weird). Will it last for 2 years +? Will it start to malfunction as I reach the 2 year mark?

Just want people's opinions on this...

thanks!