I think there's nothing wrong with few high quantity RC days here and there. It's important to always mix things up, avoid routine, the brain seems to really love paying attention to new things and is really, really good at ignoring things it's seen a million times before (personal opinion).

And I think you must do an RC any time you think of doing one. Do not stifle the urge to check your reality. If you start suppressing RCs in the waking state, you'll start skipping them in the dream state, and miss LDs. Treasure and nurture those moments where you start thinking of your state & dreaming, those are lucid moments!

Every RC though also must receive your full attention.

But do not confuse critical reflection moments with RCs, I think some people mix them together. A RC should be quick, even when you give it your full attention. Critical reflection, though, deserves a good 30 seconds to a minute at least. A handful of those a day is probably all you need. But as for RCs, I'd say at *least* once an hour, and I'd probably prefer more, if you're not doing any form of continuous mindfulness (yes it's hard to start, but once you do it's hard to stop, and is really enjoyable....it's the best approach IMO).