The only ones I use a new atty for are the fruits as some of them can be a bit lingering (I use ONE atty for ALL my fruits btw). I've also heard the Atomic Fireball (cinamon flavor and yes like the candy of the same name) is very hard to shift out of an atty too, so that one might need its own one.
I direct drip btw, don't use carts much and I jsut shove things on top of each other. Sometimes that give me odd flavors but usually not

All my coffee/tobaccos go in the same one. Right now I have 1 for fruits, and 2 on the go for 'everything else' and one in reserve.
I don't clean them either - just blow them out and so far so good
