User blog comment:TRAPPER/How many years do you think luffys life has been shortened/@comment-3119203-20110114015524

I'd say from 10-15 years, because during the battle of marineford and in impel down, he was using gear second a lot, even if it was only for a short time. That adds on to the time while at enies lobby to amazon lily, not to mention the time he spent training. Maybe he got a way around it during the timeskip