I know before you put a car in storage say for close to a year you should change the engine oil. I have heard of people changing the oil before and after it going in storage. Why would I need to do it twice? What happens to the oil if it sits in the engine for long time between runs?
There are a million theories on this, but I have always changed the oil and filter (and driven the car ~10 miles before storing it to get fresh, hot oil everywhere) and haven't worried about changing it again after Spring came until the next normal change interval. All the oil does while in storage is pick up a little moisture from internal condensation, and that will boil off within a few miles of driving. Don't start the engine while it's in storage unless you're going to drive the car at least 10 miles - otherwise the corrosive contaminants (blow-by and rich mixture from cold operation) end up in the oil and don't get boiled off, as the oil doesn't get hot enough. Has worked for me in lots of winter-stored cars for 40 years.