I ran the avalanche numbers for my specific debts and the answer surprised me.

My debt stack: $18,000 at 22% APR (credit card), $7,500 at 11% APR (personal loan), $3,200 at 0% APR (furniture, 18 months remaining).

Avalanche (highest APR first): I'd save approximately $3,800 in interest vs minimum payments and be debt-free in 28 months.

Snowball (smallest balance first): I'd eliminate the $3,200 balance first, then the personal loan, then the credit card. Total interest savings vs minimum payments: approximately $2,900. Debt-free in 30 months.

The difference is $900 and 2 months. For some people, the psychological benefit of the snowball closing out accounts faster is worth that difference. For others, the $900 and 2 months matters. Neither is wrong — know yourself and pick accordingly.