Where you stand

I received a lump sum: inheritance, bonus, sale

If that is you, here is what this situation usually involves, in the order it usually comes up: the things worth checking, what each one is, and where the arithmetic for it lives. None of it says what to do.

1. Most windfall regrets trace to the first month, which is why the first ninety days are often spent with the money sitting in a plain savings account or Treasury bills while nothing is decided.
2. Debt with a rate above roughly 7 percent costs more each year than most investments have historically earned, which is why it is usually the first figure people compare the lump sum against.
3. Accounts with yearly limits, the HSA, the 401(k), and the IRA, have room that does not carry over; what room exists this year is on each one's landscape page.
4. Moving a lump sum in all at once and moving it in over a few months are both common, and the compounding guide shows what each has done on real years.
5. Inherited stock or property usually comes with a stepped up basis, which changes the tax on any later sale; a CPA confirms the basis before anything is sold.
6. Who knows about a windfall tends to shape what happens to it; that is a fact about people, not a rule.

Read these

Compounding, and why the early years look boring
Spreading it out and betting big: what each one protects you from
What a one percent fee costs over a working life
Inflation: the quiet subtraction