What is the length of a professional bowling lane?

depending on the definition of career, there is no set average length. They time spent Bowling in one's lifetime can vary too much. If by career you mean league bowling than it could be from age 4 for example to death if that person has the physical capabilities to continue bowling into an older age. If you mean by a professional career, the gap is obviously shorter since a bowler needs to get better in order to pursue that. However professionals tend to stop bowling on the regular PBA (professional bowlers association) around 50, but there is a senior PBA so it is once again varied a lot.