See other post. Usually if the rings are bad, you'll use oil pretty bad. If you can go 1000 miles after an oil change without adding a quart, you should be in good shape. If the compression rings are gone, you'll get a lot of blowby (oil smoke into the PCV system) and the spark plugs will foul out with oil quite often. These days you don't see a lot of ring problems due to good materials and better oils in use.