I got certified twenty years ago before a trip to the Caribbean, but haven't used it since. Being stuck in the middle of the heartland doesn't help. I had fun in the class (went through with my brother), but it did take several weeks, some studying and taking a test.
If it's going to be a one time thing like I did, you can get cruise certified which will let you scuba the one time and be done. If you plan on doing it regularly, I would get the full certification.
