Just follow all the service intervals shown in your manual and don't let your dealer sell you service you don't need such as "15K mile service" or "air induction service" (whatever that is other than more money in the dealers pocket and less in yours)
If you look at the maintenance list, certain things ARE recommended at (or about) 15K miles. Those items taken together would constitute a 15K service.
Air induction service might mean cleaning the throttle body throat and associated sensors. That MUST be done periodically but 15K sounds a little soon, unless you are in a dusty environment or have a non-stock air filter.
Things NOT on the recommended list should be avoided......unless they were recommended earlier and you didn't do it then.
I drive in normal conditions, and have had my oil and filter changed a few times now. I am at 12k miles. The induction service was described as cleaning out the exhaust and fuel system somehow. I do not understand this, nor do I know if it is something that would be worth it for keeping my car in good operating condition.
♪♫♪ "Chim chim-in-ey, chim chim-in-ey
Chim chim cher-ee!
A sweep is as lucky, as lucky can be
Chim chim-in-ey, chim chim-in-ey
Chim chim cher-oo!
Good luck will rub off when I shakes 'ands with you." ♪♫♪
More info. The manual states to replace the cabin air filter @ 15k mi, and to inspect the engine air filter. I looked them over today, and sure enough, the cabin af was very dirty, and the engine af was mostly dirty, so I stopped by Auto Zone, picked up some replacements, and changed 'em out. At AZ, the clerk tried to sell me some fuel system cleaner, but I passed.
Could the dealership have had these items in mind for their 15k mi induction service? I am thinking they did.
So, follow the manual, hold service offers to this as well, and thereby avoid unnecessary costs for maintaining my Sonata.