A home battery pays for itself only when the price spread it arbitrages, multiplied by the energy it actually delivers, outruns its net cost before the cells wear out — and at typical retail spreads near $0.18/kWh it usually does not.

Cycling harder is close to a wash once the pack is cycle-limited: doubling cycles per day halves the payback period but also halves the years of cycle life available to reach it.