I don't think you will notice much of tolerance anyway. Codeine is pretty mild stuff and there is a sort of a ceiling effect where no matter how much you take you don't get much higher. Better just stick to lower/moderate doses if you can, I've never gotten anything going above 360 mg, so you don't lose much and you are not wasting it you probably won't experience much of the tolerance building up anyway unless you are doing it for more than 3 days in a row/a week at which point you will very likely be experiencing a withdrawal at a certain degree.