Tolerance is gone after one week, you really don't need to wait a month but may choose to for personal reasons, one week is the minimum amount of time you should wait, but there are added benefits to waiting a little longer, weekly dosing can't be done forever, though I like to dose psychedelics weekly for a while a lot of the time. Personally I alternate between weekly & bi-weekly dosing for the most part which does not create tolerance.
What's more important than tolerance though is making sure you've integrated the experience, tripping before integrating a previous trip can fuck with your head afterwards, integrating trips takes about a week for me, but many need more time, which I think is why many say you should wait a month (personally I don't think waiting a month really makes any difference at all vs. waiting two weeks for the most part- but sometimes I'll do so just to take a longer break, as those are necessary from time to time).