I wax every few times I ski any ski, it varies though.
As far as tuning edges, I still have a few race skis that have edges on them, and they probably get an edge tune once a year. But I only ride them a couple times a year.
all twin tipped skis get ridden their first time out without touching the edges, then I decide I dont like it so I file them down, nice and round.
If you hit rails or anything, I wouldnt suggest sharpening your edges. I would suggest rounding them down. It seems to reduce wear and tear. Its also a little more forgiving for a lot of stuff. and obviously butters.