I'm looking into buying rollers. I have a very old magnetic trainer from Performance, and I don't use my "good" bike in it because I feel like this puts stress on the frame. Is that true? I would like my computer to work, and use my good bike.

My roller question is... just how much concentration does it take to stay upright on rollers? I was reading some old threads and someone wrote that after a time they were able to adjust their hand position without stopping !!!??? Is it really that hard? Is it more difficult to stay upright on rollers than on the road?