I had a firearms instructor tell me that you should dry fire a weapon 100 times for every practice round you put down range....
It seems like he was a little over zealous with his dry firing, but you get the point. And it is a good one.
Dry fire is a great way to get to know your gun, and feel comfortable with it. Just make sure to use snap caps if the gun can not handle it. Some pistols will beat the firing pin up (or worse) if dry fired without a snap cap.