When do I need to do a drive belt & water pump combo service?

Don’t see an engine size posted - we’ll need that information.

As Pushrod says, yes, the engine matters because if it's a 4 cylinder engine, there is no timing belt. But if it's a V6, there is. Based on what you're saying, it sounds like the vehicle is a 4 cylinder -- and that as a result, the dealer is somehow 'proactively" recommending replacement of the water pump. Truth be told, there is no point of replacing a water pump on the 4 cylinder engine, as it's not even "preventive maintenance" -- it's kind of a frivolous, unnecessary repair. The drive belt, however, should be changed after about 7 years, being a rubber component subject to temperatures, engine revolutions and age degradation. If it happens to be a V6 engine, it would have been recommended to replace your timing belt and drive belt at about 7 years -- 2 years ago. In this case, since you are in the area of the water pump while replacing the timing belt, it is not a bad idea to install one when there.