I drip now, but I still use carts when I'm driving (Remember kids, don't drip and drive!). I keep a couple each of the standard carts filled in about 3 flavors, in case I get a call and have to run out the door (I travel for work). I guess it's up to you; when I only used carts, I'd fill about 4 or 5 each morning. I do find that carts leak over time when filled, especially in the heat of the deep South. Don't leave them in the car!