Well if you've been taking care of your vehicle, then the inspections are probably not necessary, and you can do them yourself quite easily.
If you mean do you have to change the oil and replace the air filter, I would highly recommend it. Those fall under maintenance, and are in fact necessary to keep your car running well. Nissan specifies a 30,000 air filter interval, but for an $8 part, its too cheap to not replace every 15k.
I am pretty sure he meant do we have to have the dealer do the full 15k service the dealer tries to ream you for to have the warranty honored.
I think not.
When I pulled in for my 15k check, I made them read the things they were going to do.
Me--"the timing is fine".
Them--"check idle speed".
Me--"Listen to it and look at my tach--looks good to me".
I told them to change the oil and filter and rotate the tires, I can handle the rest.