Throttle body is the valve or flap that is connected to the accelerator cable, as you press down on the accelerator pedal the cable opens a flap allowing more air to enter the engine. The throttle housing gets carbon deposit build up over time and may require cleaning to maintain a smooth idle. There is a lot of debate in the industry about the "selling" of fuel injection cleaning as part of a general service. Honda officially do not say it is required and has sent a letter to all of its dealers saying that yet many Honda dealers say it needs to be done. I think it only needs to be done if you have a rough unstable idle of emission failure. The intake Exhaust gas recirculation passages do plug up and get restricted in the intake manifolds on a lot of Hondas I wonder if this is what they are suggesting be cleaned.
Caulk up "induction service" or "injection cleaning" in the same arena of useless services as "underbody coating" or "paint protection". Most vehicles do not require this service at all if your air filter is changed regularly. The throttle body is responsible for managing the amount of air entering the engine. This air is filtered prior to entering the intake manifold. If you really want to clean out your throttle body, they sell cans of intake cleaner for about $4-5. Remove the air intake hose connected to the throttle body, start the engine and spray the 'butterfly' of the throttle body as you rev the engine. This will help to dissolve and remove any residue or dirt in the throttle body.
If you car has over 100k miles i would do it- but at a way lower cost and not very often.
One of the cheapest places i can find is Brake Check-make a appointment online you will get 15-20% off your service.Here in Texas they only charge around $40.00 for a fuel induction service.It pushes the additives and build up through with a machine and white smoke will come out your pipes when build up gets burned up and off.
There is no way a newer car needs this done.