Hard to justify the price of one of these things as a "maintenance necessity" - although it does make many underwater maintenance chores simpler. And if you enjoy snorkeling or diving, hookah-kits are amazing and fun to use - and might help you to justify the purchase. The very best ones are Air Line by J Sink in Ocala, Florida (
www.airlinebyjsink.com). Lots of great features that make maintenance simpler and ensure longevity (of both you AND the unit.)
There are indeed some folks who have built their own hookahs for less money, but if you decide to go that route, be VERY careful and do your homework. Using a Harbor Freight or some other cheap compressor (whether supposedly "oil-less" or not) will have you breathing atomized oil - and the chances of blackout from breathing atomized oil are quite high. Aspiration pneumonitis or lipoid pneumonia is not a great way to die. Also, using cheaper, non-scuba type hoses will have you breathing rubber particles too. Not to even mention the problems with the potential of inhaling exhaust fumes through your rig...