See this for @EvZ 's fantastic work on sample size for binary vs. continuous outcome trials.
Adding to James’ excellent thoughts, a reason that stratifying by pragmatic/cluster-randomized vs. traditional RCTs is important is that cluster-randomized trials need much larger sample sizes to have the same power as individual-randomized trials. It is also much easier to accrue patients since they usually don’t use informed consent. That is related to another criterion: first-in-man RCTs vs. RCTs of accepted practices / treatments / repurposed drugs.