IMHO: FWIW, The manual is the bible for your car. the DEALER (read dealer service writer) is NOT the authoritative be all, end all for looking out for YOUR (or your car) best interest. The service writer is looking out for the dealerships ‘bottom line,’ not yours.
When you go to a dealer for service, they give you a write up sheet that they want you to sign to ‘authorize’ the work they recommend. See how they get off the hook? they advise you what to do to the car (needed or not) and when you sign it, you have taken responsibility for having the work (whether needed, or just dealer profit) done and you pay the bill.
You CAN (and should) actually read each item. You will notice they are separated into separate topics. The heading for each topic will have one of two words in it: required, or recommended. That is your cue to decipher what is ‘needed’ versus what they recommend.
also, the required items will (by coincidence) be the ones in your manual, considering your vehicles age, mileage, and what has been done before. The recommended items will be pure profit for the dealership.
Im not saying that anything the dealer ‘recommends’ will be unnecessary, but by and large they foist a bunch of useless crap on you to pad the bill.
The cure? Find a good, reputable, (with recommendations) mechanic to work on your car. you will soon learn to TRUST your mechanic. Once you have found a reputable guy stick with him. they are like gold! You DON’T have to go to a dealership for routine repairs that are NOT under warranty. EVER!