We keep a tally of what comes through the workshop door. Three faults account for most of it, and all three are visible in a ten-minute check with no tools beyond a pump and a hex key.
Tyre pressure first: an under-inflated tyre on a heavy e-bike pinch-flats on the first kerb and drags 15% off your range in the meantime. Then torque arms — the small plates that stop a hub motor twisting in the dropouts. A loose torque arm is a slow-motion frame failure.
Finally, brake bite. Pull each lever and note where it engages. If the bite point has moved towards the bar since last month, the pads are going or there is air in the line. Neither is urgent today; both are urgent on a hill.