In the sixties we went cycle camping in Norway. At one supermarket, full of interesting food we did not get in England like whale, reindeer sausage, we bought some cheese including one small piece of "blue", more like grey, cheese called Gamelost (translation old cheese) The three of use had a taste but it was so strong that I was the only one who had any more. For the rest of the holiday I eat a bit most days. You only needed a bit. It stayed in its bag, getting a bit runny, for more than a fortnight. That fortnight was a Norweigian miracle, midnight dusk and no rain, hot for Norway. I was never sick and only went off it when we got home.
6 Months later I came across a plastic bag in a cupboard. It was the remains of the very Gamelost. It smelt like fishermans maggots left in a closed tin to rot for months.
By then I thought it was inedible so I didnt try. It was still grey, but not such a nice grey.
So even if you start with old cheese you have at least another fortnight. When it gets to the stage that you dont like the smell perhaps that is the time to stop eating it.