I agree, I also do not worry about the lines or the cooler contents.
As I change the
oil regularly, I find that the contents of the lines and cooler just mix in and eventually get cleared.
I have always primmed the filter prior to replacing and starting.
How often I top up is another story, as I find that I use a bit of
oil when running. Don't know what others are using, but think I would use a pint about 800 miles. Guessing here, as I top up/check every drive from a bulk
oil container.
Bernie
Cheers
Bernie