The greatest thing about software is that it's ever changing. We used helpdesk systems in 2000, changed to others in 2003, a new one again in 2004, and then BACK to the original from 2000 which had vastly improved. Then a new system came out, we moved to that, it was wonderful, but didn't have some features we would have liked to see, so we moved to another.
While it may seem that there was a lot of bouncing around, the client didn't get to see any of it really. All the training and learning was by our admins and tech support as it showed different data or displayed differently.
So while you may like a certain script now, always be looking out for the next greatest thing, it could be right there
I do checks of various scripts/programs that we use almost monthly, and while we've paid a pretty penny for OWNED licenses (never rented), there's no hesitation to change to something better if it will be of benefit.