Age is the wrong number here. An eight-year-old lawn tractor might have 150 hours on it or 900, and no repair decision survives a variable that wide. The right number is on the machine, and the arithmetic is one division: What the repair costs ÷ the hours the machine has left — compared against —…
On a two-stage or three-stage machine, almost always. A realistic small repair reconstructs to $130–$325 against a $785–$2,015 two-stage replacement — Lawn Love’s typical band, with a three-stage’s starting at $1,800 — and the machines routinely outlive the ten-year lifespan Consumer Reports assumes for them. On a single-stage, the answer has surprisingly little to do…
On a walk-behind mower what broke answers the question — not what the repair costs, and not how old the machine is — because the bills are bunched at the two ends and the middle, where break-even arithmetic would earn its keep, is empty. Look at the two columns together: What failed Typical shop bill…