My base and edges usually take a hell of a beating on rocks and trees. For the most part a wax and sharpen does the trick (prob every 3rd time out). I usually do a board tune only when I fuck the base to the point of needing P-Tex or a base grind, and I ride between 15-20 times a season (not counting trips to the local hill). I know end of season the wax job is a little different because you usually don't scrape. But for routine maintenance, it'll be pretty obvious when you need a tune up.
'12 Lib Tech T.rice / '12 Burton Cartels
'10 CustomX / '10 Co2 EST