Just got Autolite APP103's and Taylor 8.2mm wires. Will install at 80k miles [about 650 left to go] when I change oil and rotate tires. They say plugs are good for 100k miles but my experience has been that even though they still work, performance has degraded noticeably. Engine doesn't start quite as fast. First few seconds of idle might be a bit rough. Fuel economy is degrade. All of these changes are so gradual that we hardly notice them. As gap grows the plugs will still be fine until, one day, the gap is just too big and then we feel the problem. I'd rather change them earlier than to wait for that day as my son-iin-law did with his Escort...it would barely run. New plugs and wires and it was like new.