A clothes dryer needs everyday attention and periodic attention. The lint screen gets cleaned after every load. The vent run behind the dryer gets checked on a regular schedule. Knowing which task is yours keeps the dryer working the way it was planned.
Clean the screen after every load
Pull the lint screen after every load and clear it by hand. Look at the screen housing for a film of lint. A film means air is moving less freely than it should, and the dryer will run longer to finish a load. Wipe the drum opening and the door seal while you are there.
Check the outdoor hood
Go outside and look at the exhaust hood while the dryer runs. Air should push the flap open. If the flap stays closed, or if lint collects around the opening, clear it. Note any nest or debris near the hood.
Check the duct behind the dryer
Pull the dryer out far enough to see the transition duct and the connection at the back. Check for kinks, crushing, or a loose clamp. A flexible connector with kinks holds lint and slows air. Note the connector material on your system file. Replace it only with the type the manufacturer's paper lists.
Watch the run time
Notice when loads start taking longer than usual. Longer runs are a useful sign to check the screen, the hood, and the duct before you call anyone. Write down what you found so the next check has a record to compare against.
Where the owner checks stop
The lint screen, the hood, and the visible duct are owner checks. Gas connections, electrical work, and any change to the duct route belong to a trade. A deep cleaning of a long or bent run usually goes to a professional who has the right tools. Ask them to note the run length and bends on the paperwork so your file stays complete.
The service life and planning notes for the dryer are on its own page. Use them to decide when a replacement comparison is worth starting.