You could simply have a file where, for each day, you mark off whether you’ve gone the whole day without suffering or not.
Note that suffering doesn’t have to be anything extreme. Suppose you have to carry some heavy, uncomfortable bags, or you feel mild annoyance about somebody saying something inappropriate. Those are still sources of suffering, if only mild ones.
You could simply have a file where, for each day, you mark off whether you’ve gone the whole day without suffering or not.
Note that suffering doesn’t have to be anything extreme. Suppose you have to carry some heavy, uncomfortable bags, or you feel mild annoyance about somebody saying something inappropriate. Those are still sources of suffering, if only mild ones.