A large share of the repairs we attend started as something small and ignorable: lint packed along a dryer duct, a dishwasher filter that had never been lifted out, a front-load door boot holding water after every wash, condenser coils under a blanket of dust, or an ice maker slowly furring up with scale. None of them look urgent. All of them shorten the life of the appliance and several of them end in a call-out.
A maintenance visit works through those points and shows you which ones you can stay on top of yourself between visits. Dryer venting is handled as a safety job rather than a performance one, because a duct packed with lint is how laundry fires start. Where we find something already failing, you get the finding and the price before any repair work begins.