Nozzle heat cool cycles

I have an A1 Mini without AMS. When I load filament before a print, the load filament process heats up the hotend to around 250 (PLA). As soon as the load completes the nozzle starts cooling. It may be down to 150 or so before it starts heating up at the start of print.

Similarly, when I am finished printing for a while, I want to unload the filament, but the nozzle has cooled off after the print and it has to heat up again to unload the filament.

Do the extra heating and cooling cycles shorten the life of the nozzle and/or heater?

No.
If you move the hotend over to the right & activate the cutter, you won’t have to unload the filament.

Thank you for the suggestion. I see how you can remove the filament, but that would leave filament between the cutter and the nozle. Does leaving filament in the nozzle cause problems? Particularly if the filament deteriorates as it absorbs moisture?

Unloading the filament will still leave filament in the nozzle.
The only way to get most of it out would be by doing a cold pull.

With the Bambu it will auto purge out the old filament when it loads next.
Most other printers, you have to do a manual purge yourself.