A high-output cordless leaf blower is convenient but puts heavy demand on batteries and motor controllers, especially when turbo mode is used frequently. Typical failures include battery packs losing capacity, trigger switches, and electronic speed controllers; less commonly, the impeller can get damaged by debris ingestion.
Repair is usually worthwhile when the blower body is fine and the fix is a switch or controller under the threshold-particularly if you already own other batteries in the same platform. Replacement becomes more attractive when both the battery and tool are degraded (short runtime plus power drop), because stacked costs can exceed the threshold quickly.
Also consider ecosystem value: if you have several tools sharing the same batteries, repairing the tool may be preferable; if you're moving platforms, replacing can simplify future ownership.