Originally Posted by FlyerJosh

Many folks have no clue how much deice fluid costs. Here's a rough idea... Type 1 is about $9/gallon in bulk. Type 4 is close to $15/gallon. If you don't have a bulk rate, it's even more (I've seen FBOs charge as much as $25/gallon for type 4).

Just food for thought. That said, as has been stated before, if in doubt, deice/antiice. However, I've seen many instances of deice "lemmings"... when it's not really necessary.