Until them, I've learned not to change anything unless there is a very strong reason. It radically cuts down on the amount of confusing surprises.

When I was an IT Administrator, we had Office 2000, and never upgraded, except for the odd plugin to be Office 2007 compatible. Nobody needed training, everything worked as expected. Sure, nobody knew the new flowy ribbon GUI, but nobody cared because they were getting stuff done, and moving on with their life.

I had done my job and successfully absorbed as much uncertainty from their computer use as possible.