Selling planes

When is the best time to sell planes would it be best to sell it off at large check ?

I didnt sell my widebodies at Large Check. Coz 77W earns 11k per route, A35K earns 9k and 789 around 8k. I am considering a fair distance. Not too long not too short. Even in that case this large check cost is covered in a few trips. Imo its all about revenue.

Well´╝îyou dont get sliver eagles at D checks like the old time, so the only reason to sell a plane is to change aircraft or close a route.