How do I know if the lab my dentist uses for veneer fabrication is a quality lab?

just ask for pre and post result of previously done patient. if you are happy with yr cosmetic dentist's result , go ahead. good lab is important but one more thing is also very important is yr dentists coordination with lab. so if yr dentist is comfortable with one lab and providing very good result , in that no need to force dentist to change lab.

The best way to ensure you are getting quality veneers is by choosing a high end dentist who is a cosmetic dentist and does this type of work routinely. Look at the Dr's website, what are the samples, the patients (models, tv personalities) and you can see very quickly who is an expert and who is just doing it once a while. You are also able to visit the lab, thus making your decision as your are checking out the lab, the cleansiness and the cases on their lab bench.