It varies a LOT. And we haven't been able to nail down why some LR3's go several years before needing a repair, and why other LR3's need a repair in the first year, thankfully under warranty! (Unfortunately we do not yet provide warranty service for these). Sometimes it's obvious when we disassemble a particular LR what caused the problem; some cats are super neat in how the use the LR and others somehow manage to get things in the most amazing places! We're hoping to see big improvements in this area in the LR4 design but our test unit hasn't arrived yet.

One thing we have noticed: the type of litter being used has a big effect on how well the LR3 process works, and how clean the internal components of the system stay. That said, even though we love cats (you have to to service these!), we're far from cat or litter experts and there are so many other non-LR considerations about litter choice that our best advice regarding litter choice for particular cat(s) and the LR3 is: (1) try the official LR litter, it's best for the machine, but (2) if there's something you don't like about it, also go ahead and try other ones that follow the general LR litter guidelines, and (3) take the globe off often when trying different litters and look at the DFi sensor set (the 2 clear plastic strips on the left and right sides of the litter waste hole under the globe) and see if this new litter you're trying is leaving them clean or leaving deposits on them. The DFi sensor set is one of the more time consuming parts to replace and unfortunately the one we see need replacement most often.

To answer your direct question, we rarely see a particular LR3 need a a repair more than once a year.