I vacuum once a week normally and and twice if company is expected for a day by pool. $700 every three years isn't worth it to me. Can't imagine if I had to replace everything at that rate, appliances, tires for vehicle, etc. I'm betting they are purposely made to last X amount of time like air conditioners... Home a/c used to last 15 years easily, now you are lucky to get 10...I don't mind paying good money for quality items that last, I,e. I had no reservations spending $1800 on a two channel stereo amp for the home ,but that amp will last 20 years plus easily. Comparing the SWG to a robotic cleaner is apples vs oranges IMO. The SWG is a needed part of the pool. Yes lifespan is relatively short but I would not own a pool without one.