Where you stand

I am carrying credit card or high interest debt

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. Interest on a balance above roughly 7 percent is a cost no investment reliably outruns, except an employer match, which is why the two are usually compared first.
2. Every balance has a rate; the debt payoff calculator shows what ordering by highest rate costs against ordering by smallest balance, in dollars and months.
3. Card issuers can lower a rate on request, and many do; a phone call is the only cost of asking.
4. A 0 percent balance transfer carries a fee and an end date; the arithmetic of the fee against the interest saved is on the debt page.
5. A small cash buffer kept while paying down is what keeps a flat tire from going back on the card; one month of bills is the usual figure.

Read these

Compounding, and why the early years look boring
What a one percent fee costs over a working life