Checking fluids sounds like the smallest decision in car ownership, and that is why it gets skipped. The question is not how to read a dipstick. The question is who checks it, who tops it up, who writes it down, and whether the contract you hold assumes that work already happened.
Sort the fluids by who touches them
Engine oil, coolant, brake fluid, power steering fluid, transmission fluid where the vehicle uses it, and washer fluid each have a reservoir, a dipstick, or a sight glass, and each carries a different level of risk when it runs low. Washer fluid is a refill you can do in the driveway. Brake fluid is a level check that can point to a leak or to worn pads, so a low reading is a finding to hand to a technician. Oil and coolant sit between the two. A top-off is simple, but a level that keeps dropping between visits is a sign of a problem that someone qualified should look at.
Read what the contract says about routine care
Service contracts are written around mechanical failure, not around the routine work that keeps an engine healthy. Many contract forms say the owner is responsible for maintenance at the intervals in the owner's manual, and some ask you to keep receipts or other proof that the work was done. A claim can be denied or delayed when the paper trail is missing. Find the maintenance section, then find the words that describe what counts as proof: a receipt, a logged service entry, a shop statement, or something else. Those words decide whether a fluid check is a simple habit or a gap that gets used against you later.
Decide who does each job before you need it
Write a short list for the car. Name who checks the oil level each month, who buys and fills the coolant, who looks at the brake fluid at each oil change, and who keeps the receipts. For each line, name a person, not a shop. If the answer is the shop, find out whether the shop checks fluid levels as part of the visit or only changes what appears on the invoice. Ask the shop to write the levels on the paper, not just the parts and labor.
Questions to ask before you sign
Ask the seller or provider these questions, and write down the answers. Does the contract require fluid changes at a set interval, or does it refer to maintenance in general? Does it name specific fluids? What proof do they accept, and will they accept a receipt from an independent shop as well as a dealer? If a fluid change is missed, does the gap affect only the part that failed, or the whole claim? Who is responsible for handling used fluid? Can you get a copy of the maintenance section before you commit to anything?
Where to check the published terms
If you want to see how contracts word their maintenance rules, start with the providers that post a sample contract you can read before you buy. The list of companies that post a sample contract is a sensible starting point. Read the maintenance paragraph in each sample, and compare the exact words side by side rather than trusting a summary, including this one.
What a fluid check does not replace
A fluid check is not a diagnosis. If a level drops quickly, if a fluid looks or smells wrong, or if a warning light comes on, stop treating it as a top-off job and take the car to a qualified technician. Contracts usually expect that kind of judgment to come from a shop, and you should expect the same from yourself.