There's a clue or two in that Roomba story. Joel says that "My floors too dirty to use my Scooba." If he has been using a Roomba under such severe conditions, with massive pet hair as well, then it would be obvious that those conditions would lead to an early demise. Pet hair in particular is lethal to a roomba in any large quantity. The hair accumulates down in the bushings and turns into abrasive rope slowing the machine down and even melting the plastic bushing assembly.

The other clue is that the Scooba is great for kitchen floors where it can handle food droppings quite handily. The Roomba has a very bad time with sticky food substances.

I had the same battery failure with the Scooba and they sent me a replacement battery and a firmware update to my door in about 36 hours.

His pink and grey machines are all second gen machines. While having some slight improvements over gen 1 grey old-timers, the gen 2 machines were over-engineered and have longevity issues. The best answer is to buy one of the new 530 roombas and sell the husks on eBay for surprising good money.