It's a good idea to do something
We use this for giving someone advice about what they should do
My question is: can we add a prepositional phrase (e.g. for + an object pronoun) to be specific about the person we think should do that thing? Or it's a fixed expression and it's used just for you and not other persons?
e.g.
It's a good idea for us/you/him/them to leave the car outside.
The sentence you are asking about
It's a good idea for you to leave the car outside.
It's a good idea for him to leave the car outside.
It's a good idea for them to leave the car outside.
It's a good idea for us to leave the car outside.
are grammatically correct and specifically qualifies whom the idea is good for.
Other prepositions which can be used as qualifiers are
It's a good idea in general to leave the car outside.
It's a good idea, between you and me, to leave the car outside.
It's a good idea over time to leave the car outside.
It's a good idea before anything else to leave the car outside.
