Reefing requires commitment and effort. Mixing saltwater, or buying jug of saltwater, constant care involved, and of course the cost is nothing to sneeze at. If I want to go on vacation, just like with other pets - I need to plan for someone to keep an eye on this and feed. This is also such a high tolerance for patient type of hobby it can lead to people feeling burned out before they see the long term results of years of hard work. A lot of people see a tank and thing, "I can do that" and then try to move too fast and boom, system crash and they are so heart broken they don't want to go through that again. It is a great hobby if you have the patience, money, and according to my wife are just nuts enough to stick with it :)