For us, it’s paying off our mortgage early, maxing our HSA, and funding 529s for the kids to keep our MAGI manageable in early retirement. We could never stay below 400% FPL with a HCOL mortgage and want our kids to have the option of graduating college without debt (saving enough for a public 4-year university, if they decide on private or grad school then they’ll have to take out loans).

What are you prepaying now in your earning years to optimize your income and spending later on?