The Denver area sits in a severe cold climate band, and that matters more for rollers than most people expect. Steel rollers stiffen and contract in low temperatures, and the grease inside stem bearings thickens, which is why the knocking sound is often worse on the first hard-freeze morning than it is by midday. Homes built around Cherry Creek's 1982 median are old enough that most original rollers have seen forty-plus winters of that cycle - expand, contract, expand again - and the metal fatigues at the axle even if the roller wheel itself still looks fine. Add in a metro household income median of $147,618 for the broader service area, which tends to mean owners fix a roller problem before it becomes a track or opener problem, rather than letting it run until something breaks.