I imagine it also depends on vehicle usage. If you’re mostly on the highway, greasing every oil change is probably more than sufficient. If you're going off-roading and ESPECIALLY if parts are submerged, then absolutely greasing needs to be done more often...once a month for dirt road, and immediately after getting out of the water if parts get submerged.I would say you need to grease way more often than every oil change. More like every other week, or at least once a month.
Kinda depends on the grease you use though.
I've been using marine-grade grease for everything except the front wheel bearings (they got Amsoil synthetic) and greasing every oil change has served me well for 80K+ miles