Every service contract and warranty has a clock, and the clock does not always start when you sign. Before you pay, find the sentence that says when coverage begins. Look for the effective date, the start date, and any phrase such as waiting period or elimination period. A waiting period is the stretch after the agreement starts during which a claim for a given part or failure is not yet accepted. It is written in the contract, not in the sales conversation.
Walk the document the way you would walk a mechanical room. Start with the effective date and compare it with the time you expect the system to need work. Then find the waiting period, if there is one, and note exactly what it applies to. Some terms apply to the whole agreement. Others apply only to certain parts, certain failures, or claims made before a set point.
Next, read the exclusions. An exclusion is a named item or condition the agreement does not take on. Wear items, cosmetic damage, damage from outside causes, and work done outside the terms the contract sets are common examples in general. Do not assume a component is covered because it sits inside the system you are buying the plan for. Ask the seller to point to the line that lists it, and read that line yourself.
Then find the pre-existing condition clause. Many agreements decline a claim for a fault that was already present, or already known, when the contract started. This is where the age of the equipment matters. An older unit is not a defect, but it can become the reason a fault gets read as existing before the start date. Write down the condition of the system on the day you sign. Take photographs, and copy the model and serial information from the nameplate. That record is yours to keep.
Ask these questions before you sign. When does coverage start, and does a waiting period apply to the parts this system is most likely to need? Which parts are excluded by name, and which failures are excluded by cause? How is a pre-existing condition decided, and what record would you need to show the system was working when the agreement began? Who inspects a claim, and does the work wait for your approval? Does the waiting period reset after a claim, or after a change of owner?
Keep the signed copy together with the effective date page and the exclusion page. A folder that holds only the sales summary is not the contract. If the terms are unclear, put the question in writing and keep the answer with the agreement.
The planning date for the equipment does not change because a contract was signed. Use the install year and the typical service life on the system page for your unit, such as the Gas Furnace or Heat Pump guide, to set the planning window. For the published figures across the household equipment, use the ranked table of typical service life on this site. The contract only sets the terms under which a claim is read, and the age of the system stays the same either way.