[earlyriser]

It's incredible how many folks are saying to pay it forward when OP specifically ask about paying it back (the fwd is addressed in the initial prompt).

Call them, write letters, specifically tell them how they influenced you. My MIL was a teacher and 10 years ago she received a call from a pupil (now a middle age man) and he talk with her about how much she influenced him. It has been 10 years from the call, but it's one of her favourite souvenirs.

[wepple]

I think folks are maybe saying that beyond a “thanks, what you did was really meaningful to me”, there’s often not much else. People who selflessly give are stoked to know you’ve amplified the giving and passed it on, more than any kind of paying it back.