That's not the point. It doesn't have to be weekly, or even monthly. Whatever the frequency is, Amazon is somewhat likely to already have a package headed to th

That's not the point. It doesn't have to be weekly, or even monthly. Whatever the frequency is, Amazon is somewhat likely to already have a package headed to the customer within that interval (much more likely that a dedicated prescription store, certainly). The advantage is actually greater with less-frequent refills, as the probability of having another package they can piggyback on within an acceptable window becomes higher the less frequent the refills are.