I'm often asked to help get rid of extra stuff in the homes of my clients. Primarily, this is focused on mail. It comes in easily but it does not go out the door as easily for some.
For smaller jobs I roll up my sleeves and work with my clients to declutter their spaces. It makes them happy to see order and cleanliness. It's also safer and may reduce falls if they don't have to navigate through piles of their things on the floor.
For larger jobs, I have referred organizing companies and folks that will pick up large loads of junk. That's harder to do because most of my clients want to see everything that's going out the door. So, cupboard by cupboard, drawer by drawer, we can make a small dent each visit.
I normally figure in the price of a helper to do more of the heavy lifting. Remember to wear gloves and a dust mask to protect yourself from dust etc...