Extended warranty contracts caution you to keep up with your vehicle’s maintenance requirements according to the manufacturer’s instructions in the owner’s manual.
You must complete all the required maintenance, oil changes, fluids, etc. and only use approved parts and liquids.
Keep all your receipts as proof that you had all proper maintenance performed.
Your owner’s manual has maintenance schedules for “normal” and “more severe” driving conditions of your car. You are required to follow the maintenance schedule that applies to your operating conditions to keep your extended car warranty in force.
Don’t invalidate your extended warranty through neglect or not understanding the terms of your contract.