The record is held (supposedly) by a Japanese man named Shigechiyo Izumi, who worked 98 years. From age 7 to 105! :o
Found it while browsing the website with the longest domain-name: http://thelongestlistofthelongeststuffatthelongestdomainnameatlonglast.com/long148.html
Another website, which ties the above mentioned one as regards length, can be found here.
NB: Not for 56kers! It’ll load about a megabyte worth of decimal places of pi!