The veneer that my dentist put on in May fell off the other day. I'm getting it put back on today but will I be expected to pay for it or will I be covered by some sort of guarantee since it only lasted 7 months?
That's between you and the dentist. I suggest getting the work done first, then discussing his warranty practices. A happy dentist will do a better job than one who thinks he is working for free.
ed
One thing that really frustrates me about dentists is that you get no guarantee for the work they do. So if you have a filling and it falls out within a month they are not obliged to replace it Free of Charge.