This is a good point.Depends a bit on your stakes too. If you're playing $10 buy ins, a new $20 to $30 setup everytime is just silly. If you're playing $1000 buy ins, yeah I'd be busting out new cards every other game if not every time.
I just went through the last deck I used once, at the previous home game, for the home game I was having and had to take one of the Q's out of service. So not all plastic decks are good necessarily more than one time. (I had this happened to a Copag deck too) I now have a deck for replacement of bad cards for new decks going forward. I prefer to use a plastic deck for as many uses as possible to get life out of it.