The axiom that works is: reef the first time it occurs to you that maybe you should. And then reef again the same way. and so on.
I would agree that if you're trying to get to weather, pinching (to a point) will get rid of some heel, but you need to be careful not to stop the boat. Some boats handle this mode better than others. I would not suggest bearing off to reef the main either.. it puts more loads on everything. Continue sailing close hauled on the headsail only, release the mainsheet and vang and put a tuck in. Once the halyard is retensioned, sheet in and off you go.
You'll rarely regret reefing early unless the wind disappears, in which case it's easy to restore the full sail... much easier than trying to put in a couple of reefs too late.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)