Everything I get done is covered at the hospital on post however like lildoving said there can be deductibles if you're not going on post. If you're not sure it's best to call tri-care and find out specifically what they'll cover for whomever you're seeing and what they'll expect you to cover.
I do have tricare and I have been going to a hospital that accepts tricare however I have been paying my share also....in my opinion if you go on base yes you are fully covered otherwise I so not believe so... I could not have gone on base because my husband deploys and I am living extremely fat from a base.