Originally Posted by Grumpyaviator

If you’re 60;
67 trips x 60 months = 4020 total trips.
4020/100=40.2 months at 100 trips/mo.
If you work five years from 60-65, you’ve worked for free for 3.35 years (60-63) to earn 100tfp/mo for the last 1.65 years of your career.

If you’re 62;
67tfp x 36 months = 2412 total trips.
You work for free From 62-64 to make 100 tfp/month your last year.