Before you step your way into a cosmetic's dentist's office, it helps to know what exactly you want to correct. Many dentists will try to lure you into buying more than what you actually need. In the case of veneers, they will most likely try to convince you to get porcelain veneers - the most expensive veneers money can buy.
Common dental problems including tooth chips or gaps do not require the use of porcelain veneers to get fixed. While porcelain veneers certainly do sound lucrative, they should be used to mask other, more significant dental problems. A simple and cheap composite resin veneer can make you teeth look millions of times better at a reduced cost. Further, composite veneers only require one dental visit to be installed (as they require no lab wait).
If your dental issue requires you to get porcelain veneers, don't be fooled into getting more of your teeth done for a proper blend. A cosmetic dentist can make sure your dental veneers match the existing color of your teeth.
In conclusion, I would likely to caution you to be very careful when going in for a veneer procedure. You can easily be tricked into spending more money than a dental issue warrants. Be careful and enjoy your new smile!