Can i ask what kind you use? I don't like the ones that you have to
buy disposable receptacles of, but I got one that dumped into plastic bags (like the kind you get when shopping at safeway), and it broke down in about a month and 1/2 (just long enough for the warranty to expire).
I have a Smart Scoop which uses the plastic bags. We have had it for 2 yrs and it is still going strong. I probably will not
buy another one though because it throws clumped litter out the end due to the design.
My other cat box is a Littermaid. I have been using the various versions of them for 10 yrs and realize they generally do not last more than 1 - 1.5 yrs before breaking. While they do work, they are great and allow me to use 1 cat box for every 2 cats.
With the Smart Scoop and the Littermaid, I empty the holding containers daily and when I do, I also scoop through the litter. I wash and reuse the plastic bags and the plastic containers because I hate to be wasteful. They usually last anywhere from 1 - 3 months.
A few years ago we bought a Cat Genie which is one of the self cleaning boxes that also washes the litter. It was an early version and had a lot of issues plus my Ragdoll cat hated it. We are considering buying another Cat Genie or one of the other brands since they have gotten better.
One other thing, I have tried about every cat litter on the market and the best yet is "Special Kitty" from Wal Mart. They have 2 versions of clumping litter, one in an orange box and one in a maroon box. The one in the maroon box is the best and inexpensive.