When to use rafts?

Has anyone tried different scenarios and come up with any conclusions as to when rafts are required? I love my Cetus thus far, but I do wish I didn't have to waste so much filament on rafts, but I'm nervous not to, lest I end up wasting an entire print.

Rafts dones't really wates that much...1 to 2 grams at the most. It's also helps level out the base before the actual print of teh part starts (if teh palte iself is slightly off). If you dont want to use a raft, you need to print closer to the plate. Liek ive' mentioned in anothe rpost, I use the nozzle offset for that. Add a .2 or .3 to the offset and print without a raft or else the nozzle will e too far away and it wont stick. Their coating works really well, I used a builtTak for a few tries and I took it off...just didn't stick as well. I ahve a PrintNZ coming nex week...hopefully it will do better lol.