Repairs are the reliable traffic. A service, a puncture, gears that will not index: those searches happen all year, come from a short distance away and turn into work the same week.
Electric servicing is the gap. Many shops still cannot diagnose the systems, so a shop that names the brands it is trained on picks up work from a wide area and at a much higher rate.
Spring is the wave. The first warm weekend produces a fortnight of bikes coming out of sheds, and the shops that ranked for servicing in February take the whole of it.
Children's bikes bring families back every couple of years. It is low-value work with unusually high loyalty, and almost nobody writes about outgrowing a frame size.