I do take skulls when it's fair to do so. However with all respect to the clock (even a slow one) we both have stuff unrelated to chess, so I'd appreciate some restraint when the outcome is unclear.
For what it's worth I will not consider myself defeated where you decide to take a timeout when you're objectively losing. This happens often enough, from players of all levels who really should know better, that I'm inclined to say online correspondence chess isn't for me. I suppose it be no great loss.