I do think an
oil analysis would show the
oil after 1500 miles was still serviceable and it is easy to spend another guys money BUT spoil yourself, change it in the fall. Even if it just makes you feel like you are trying to do the right thing. I also think spinning the engine over to wet the seals and compress different V springs is a good thing.
On our race engines we back all the pressure off the valve springs if going to store very long. Granted I am talking about some wild spring pressures but it also seals each cylinder a little better.