Dryer vent safety
The air-flow service that's really about fire prevention.
Why this one matters most
Lint is highly flammable, and a clogged dryer vent is a recognized cause of home fires. It also makes the dryer work harder and last less long. Of everything in this category, dryer vent cleaning has the clearest, most concrete payoff.
Signs worth acting on: clothes taking multiple cycles to dry, the dryer running hot, or a burning smell.