A tuff question to answer, and one that everyone will have an opinion on you can bet. Depends on how deep your pockets are I guess. A lot of people, like myself who can get skis at cost, get at least a couple of pairs a year.Are they shot? No, but I like to get rid of them while they still have some retail value left.
I worked in a ski shop for quite q few years. We used to tear old skis and broken skis apart to see how the core materials held up.My acessment, depending on the abuse factor, was that 100 days on a pair of skis was plenty.(i'm not claiming to be an expert) just a shop junkies opinion. I think it also matters what the core material is made of also. How many times has the ski been tuned? Is there any base left? Is there any metal edge left? You can only base grind a ski so many times you know, before you get to the core. How much flex and rebound does the ski have left? Only you the skier who skies it can answer that question. Demo a new pair and compare.
I just sold my BanditX's after two years of use. Do to shortened ski seasons, they had about 100 days on them. Still good condition, lost some life, still got base. And I still got $250 for them.
So, as the debate begins, I say 100 days of hard skiing on a pair of skis is plenty.