wax new skis with SKI wax every week at least. It signifigantly improves the life of them and the performance. After the first 2 months or so, wax them every month, or whenever they feel they are getting slow.
from our local shop technician who has been working in the tech shop for 20+ years we should be waxing our skis every second or third time we go skiing.
I wouldn't tune the edges on skis I did rails on at all cuz you'll just keep griding your edge away, cept maybe like once or twice a season if you really want to, but then you just have to get 'em detuned again for them to slide well anyway.