42 with three disk fusion, i couldn`t think of a better way to stretch those hams then 6hrs in a giant oak, but on other hand i have my two boys learning, and we just bought a 20 ton p&h crane
I'm 49 now,had triple bypass April 23 ,was back in a tree in July.
I still work full days, but only climb2-3hrs per day max.
Like others have said,probably do it till I keel over in one.