Brick is the default, and it is a decision
Denver built in brick for most of its history, so a large share of the houses you see are masonry with painted wood trim, porches and soffits. Painting brick that has never been painted is effectively permanent, and it needs a breathable masonry coating rather than house paint. Most Denver exteriors we price are really trim, porch and window jobs wrapped around brick.
Old houses, old paint
More than a third of Denver homes were built before 1960. Porch ceilings, window sashes and stair trim in those houses commonly carry several generations of coatings, and the bottom layers are the ones most likely to contain lead. Scraping them is controlled work, not a quick pass with a heat gun.
Alleys, tight lots and street parking
Many older neighborhoods have detached garages on the alley, five-foot side setbacks and no driveway. Ladders, drop cloths, containment and a place to park the trailer get planned before the first day, and neighbors get a heads-up when a side yard is shared.
Newer Denver is a different job
Stapleton-era Central Park, Green Valley Ranch and the infill rowhomes around the light rail are mostly fiber cement and engineered trim on their first or second repaint. There the work is caulk replacement, sun-faded south and west walls, and following any community color rules.