In TN we had to do it every week for weeks. Fall lasts so long there, because it doesn’t get very cold very fast. The leaves covering the grass a long time would likely hurt the grass. Plus, the quantity of leaves would have been huge if we had waited until fall was over. We had trees all around our property, we basically lived in the woods there. The leaves could have been up to my waist in some areas if we had waited for weeks.
I think it really depends on how many leaves you are dealing with and the specific climate where you live.