Tracks and sills are cleaned on every window cleaning visit we do. They are not an upsell here, because a window with a clean pane and a track full of grit has not actually been cleaned.
Omaha runs through the freeze-thaw line dozens of times a winter. The temperature crosses freezing, water in the track melts and refreezes, and the debris sitting in there gets packed harder each cycle rather than washing out.
By March that debris is a compacted crust of ice-melt residue, road grit carried in on shoes and wind, cottonwood fluff from the previous summer, and whatever the spring storms threw at the house. It sits exactly where the sash needs to travel.
The part that matters most is the weep holes. Most modern vinyl and aluminum windows drain through small slots at the outside base of the track. That is the design, and it is how rain that gets past the seal is meant to leave. When those slots pack solid, the track becomes a shallow bathtub. Water stands in it, freezes, expands, and works on the seal and the frame. Standing water in a track is the single most common cause of sill staining and softening we find on Omaha homes.
Clearing them takes about a minute per window and almost nobody does it.