My 2009 Itasca Cambria presently has a bedroom slide out problem. I have had this issue before. Acts like a weak battery and eventually just won't go out, in is fine. So you ask, how do you know it will go in if it won't go out, well, it goes out in increments then the motor shuts down.
The fix. Remove mattress then plywood cover to expose drive screw and mechanism. Clean,clean,clean the rails of the goop that forms from dust and lubricants ,then spray with silicone or slide lube. Regular grease attracts too much dirt and forms a tacky glue like substance.
The last night of a week long trip, first Chandler Az. for the race then to Flagstaff for a visit, man was it cold. Bedroom slide fails. I'll keep you updated on my findings, maybe it will help the next guy.
To answer the question, slides have been easy to repair but require maintenance.
