15 years of flying at Fedex....
Number of guys who have said "...wish I had stayed...I would have retired by now..." --one assload
Number of guys who have said "....glad I made the clean break and didn't have to bust my butt doing both jobs..."-- ZERO.
Number of friends at Delta/American/United who rode out the post 9/11 storm and now have great seniority and a full time retirement (including a few O-6s)--quite a few.
Life gets shorter the longer you live. The next 10 years will go much faster than the last 10. Do it. It will suck some days. Do it anyway. You will not regret it.