Many car owners already change their own oil or swap wiper blades. A service contract adds a new question: which jobs are harmless to do yourself, and which should go to a shop so the paperwork stays clean? Decide that split before a claim forces the issue.
Routine care versus internal work
Simple tasks like checking fluid levels, replacing a cabin filter, or changing a bulb are different from work inside the engine, the transmission, or the braking system. A contract may require maintenance performed on a schedule and may ask for records showing it was done. Ask whether self-performed maintenance is accepted and what proof it needs.
Keep the receipts and the notes
Save receipts for parts and fluids, and write down what you did and when. The notes do not need to be elaborate. They should show the work matched the schedule in the owner manual. Keep the original packaging, or a photo of the part number, when you can.
Ask before you touch a covered part
Before you replace or repair anything the contract might cover, ask the administrator in writing whether doing it yourself affects your coverage. Do not assume a repair completed at home will be treated the same as one done by a shop. The answer may differ from contract to contract, and the written reply is what you keep.
Know your limits
Brakes, steering, fuel systems, airbags, and high-voltage components carry real safety stakes. Unless you are trained and properly equipped for them, send the work to a qualified shop and keep the invoice. A clear invoice helps your side of any later question, and it protects the people who ride in the car.