Vent window channel "Fuzzy" strip

The 55 dollar retail per door average cost is for a "kit". It includes the plastic guide/shoes that hold the glass in the channel. To do anything less than full "kit" renew wouldn't be pennywise. We can't buy those guides separately anyway. Many years ago the dealerships did offer these parts separately.
So their service dpts could replace one small part today and another tomorrow? who knows? I see the "kit' as the better plan.