Change oil for winter layup?

[RichardS]

Follow the guidance in your engine manual.
Mine is from the 1970's and gives only run time not calendar requirement, unlike my car which is on miles or months whichever is first. the idea that 50 hour old oil is going to damage an engine is frankly ridiculous despite the claims in this thread. I look forward to a chemical engineer showing me the maths and proving me wrong.

That's no chance of that as you're not wrong. If I can borrow a line from Charles Dickens (possibly), I change my oil every five years ..... whether it needs it or not.

Richard