I find most people on here that mention them say they have one a week maximum as an emergency.
I have one in the fridge that has been there for nearly seven weeks now, better to have it and not eat it then want it and cheat I thought but I was tough and fought my sugar cravings and now weeks later, thou my milk addiction took nearly four weeks to go, it's gone.
Give yourself the break from all the bad foods and be strict, you'll feel much better for it. Good luck!