I have wore contacts for about 5 years now. They are the soft, breathable, extended wear type. I wear them 24/7 and they last 30+ days. I always carry an extra set with me when I am in the field. I really love them as I feel I can actually see better than with glasses. I am a competitive shooter and they really help when I am shooting. The one thing I have noticed is I live in a really dry climate and they tend to get "dry", especially when the wind is blowing. I always carry a small dispenser of lense lube in my pocket.
If you are wearing the extended wear type, your eyes will tell you when its time to change them. Things get a little fuzzy when I look at small stuff on TV. I also will leave them out overnight to give my eyes a little rest. I still use reading glasses from WalMart.
I won't go back to glasses unless there is some problem in the future.