Heres some good info
What is the maximum depth a human can dive to
If your looking to getting into diving, your classes will cover all you need to know. Basically the deeper you go the less time you have at that depth before decompression comes into play. I'm speaking of sport diving. Commercial divers will go deeper and sometimes use mixed gasses to aid them. You won't explode but if you don't decompress you will get nitrogen bubbles in your blood...not a good thing! Unless you're looking into getting into commercial diving, decompression is not to big of an issue unless you're planning on hanging around really deep depths for long periods. I found most of my divers were around 30 feet or so. Did many repetitive dives without decompressing. Lots of neet underwater life to see. the deeper you go, the less light you have and colors start to fade, plus I found that there is less to look at as far as wild life goes. Of course there's wreck diving which can go pretty deep.