A question more directed at our pilots here, but in the course of sim flying be it FSX (Now MSFS2020) or even DCS, we all learn that higher cruising is quicker and more fuel efficient.
My question is:
Is there any guideline, formula or other aid to picking a cruise altitude?
I understand you have limits of due to say airways and the like - but at some point the extra fuel to climb must not be worth the trade, but that may be trivial in flight distance.
As an example, I recall a flight from Toronto (CYYZ) to Montreal (CYUL) in a 787 - we climbed to over 30,000ft and were only at altitude if I recall correctly for about 10 minutes before descent began. Checking flight aware for that route, I was in the ballpark - see AC402 which was an A321.