A range hood moves air and grease out of the kitchen. The grease filter catches most of what cooking throws up, and the rest travels down the duct. Keeping that path open is the owner's job, and it is most of what keeps the fan doing its work.
Know your filter type
Look at the filter before you clean it. Mesh filters trap grease in layers. Baffle filters use angled metal to turn grease out of the airstream. Both can be cleaned, but the manufacturer's note tells you whether warm soapy water is right, whether a dishwasher is allowed, and whether a degreaser is safe for the metal. Follow that note. A filter cleaned the wrong way can warp or lose its coating.
Set a cleaning rhythm
Clean the filter on a schedule that matches how you cook. A kitchen that fries or sears most nights needs the filter pulled more often than one that mostly steams vegetables. Look at the metal every few weeks. If it is dark with a greasy film, clean it. If you see grease beading and dripping when you pull the filter, the path is heavy, and it is time for a full wipe of the housing too.
Check the outside flap
Go outside, or to the exterior wall where the duct ends, and check the flap or damper. It should lift freely with the fan running and close when the fan stops. Grease and dust can stick a flap shut or hold it partly open. Wipe the flap and the screen around it. If the flap is stuck or the duct shows a visible sag, note it in your log and ask a hood or ductwork technician to look at the run.
Keep the fan and light clean
Wipe the fan housing and the light lens. Replace bulbs with the type listed on the fan label. Listen for new noise from the motor or blower. A rattle usually means something has loosened or a blade has collected grease. Write down any change in sound, because it tells the next technician what you heard and how it has changed.
Where the owner stops
Duct cleaning deep into the run, motor or blower replacement, and any electrical work at the hood or the wall belong to a qualified technician. Hire that work when the duct cannot be reached from the hood, or when the motor fails to run at all. Planning is the part you own. Check the model name and keep a note of replacement filters and parts, so the age of the hood is a planning input you already have on paper.
Keep the log
Write a short log on the inside of the cabinet door. Note each filter cleaning, each flap check, any new sound, and any part you replaced. A log turns a hood that seems to be slowing down into a record you can read.