Ah Phil, I didn't say it wouldn't work after 2 years. Just that it wouldn't be at it's best thereafter. Anyway, no splitting hairs. I just like to renew mine every 2 years, that way I feel happier. Too many electronice on modern cars to take a chance. Now in the days when I first owned cars, and they had starting handles, I could always get them started. So what if they kicked back and broke yer thumb? ;)