Thanks guys - in the past I've always run both tests at the start of the year as a general health check for the engine. I checked compression yesterday, but it was getting late and I didn't have time to run leak-down. The comp numbers were good, and more importantly (as I understand it) very consistent across all cylinders (within 5 psi). I was just wondering if that told me enough about the condition of the engine, but now I understand there are things the leakdown could find that might not show up on the compression check.