You have the DAN hotline on speed dial in your cell phone.

When out of town overnight, on business, you pack your reg and BCD, just in case.

You forget your Mum's birthday but know exactly when the lobster season opens in any given state and several other countries.

You know by heart the NDL tables for air, 32% and 36% nitrox.

You buy the best underwater housing you can find and then start saving the money to buy the camera to put in it.