preventative maintenance services

I would say no, it's just a money grab if someone at that dealership told you that you needed it. Just use top tier fuel and run some Techron fuel injector cleaner once in awhile.

Nope. With the fuels made today and injector service is hardly ever needed as long as you run top tier fuels. Throttle body cleaning should only be done if it becomes dirty under normal conditions you should be able to go at least 50000 before it needs looked at. This is of course it is maintained better than recommended intervals.

If anyone recommends fuel injector cleaner or Throttle body cleaner prior to your car having 120,000 miles on it, they're just assuming you know nothing about cars and are trying to make money on a service that they're not even going to do.