I do 3ml mixes, and use a fresh cartomizer for each mix, I do not reuse or clean carts to put another mix in them, cleaning them is not worth my time. But yes, if I am using the same mix over again, I refill/topoff them, I dont like using a cartomizer for more than a day though.
Example:
I make a 3ml mix, condom fill the cartomizer, if it taste like ...., it goes directly in the trash, even if it is ok, I may vape it for a few then throw it in the trash if its not something I would want to vape normally.
im just like you, i hate using carts for more then a day and at the first sign that i dont like it i chuck it.