Most cats are creatures of habit; if there is something they like, don't fool with it! Don't "new" or "improve" it, it won't be the same (even if it is newer or more improved!).

If I have to move a box or use a different brand of litter, I do it very, very, gradually and avoid most problems.

We did have a spot of trouble when we first moved; Binky was a bit freaked out about the new house and hid all the time. He came out one afternoon and jumped up into my papasan chair and by his posture, I KNEW what he was doing. We threw the cushion outside and washed it, but finally got rid of the chair. I wasn't going to take another chance. BUT he has never done any more peeing in the wrong places (fingers crossed!!).