Rails won't fuck your skis up too bad...you just need to hit them right. Of course, any rail will do a little bit of damage...after awhile, you'll notice.
Drop cliffs, not bombs
Make turns, not war
Totally depends on the smoothness, and slickness. But it will do damgage, it catched easier then rails do. Good rails don't do damge, they do dull your edges but that can be fixed.
IF you wanta keep your skis mint, keep to the rails and avoid kinks and dull rails.
yeah, and detune the edges! it makes rails slide so nice, and it is actually helps protect the ski. my 1260s are literally round between the bindings. as far as ledges, get a shitty pair of beat up skis off ebay with bindings. set um up, and go. and dont worry about bases, those can be fixed.