When I was playing the PSR9000, it had to have the contact strips replaced once a year. Then I went with the 740...same thing.
I have been playing the PSR2000 for over two years without so much as a hicup. (I am not sure, but I don't think the PSR2000 uses the key contact strips).

Like Gary, I carry and treat it like a new born baby...I am good to it. It is good to me.
Eddie