Understand the tradeoff clearly
Snowball pays smallest balances first to build momentum. Avalanche targets highest interest first to reduce long-term cost.
The mathematically optimal strategy may fail if it is not behaviorally sustainable in your household.
Fit strategy to cash-flow pressure
If household stress is high and motivation is fragile, momentum may matter more. If stability is improving, interest optimization becomes more practical.
Protect minimum stability while accelerating debt
Do not accelerate debt by underfunding essentials. A strategy that triggers repeated emergency borrowing will backfire.