I have been doing some traveling lately. I generally travel carry-on which means my fatboys stay at home. Took my M3 last time, but alas ran out of carts, and not about to take out a 2nd mortgage to buy more So I picked up a Wallyworld Trac II (aka, Bumpfighter) and a 10 pack of Personna carts (10 for $3.49, cheaper than feathers!). My question is how many shaves should I expect per cart. With DE's I am a 3 and out kinda guy, same for these Trac IIs?