GET / HAVE SOMETHING DONE
This construction is passive in meaning. It may describe situations where we want someone else to do something for us. If you 'have something done', you ask somebody else to do something for you.
I'm going to have my hair cut.
She's having her bedroom painted.
Amanda is having her car serviced.
In informal English, we can replace 'have' by 'get'.
The students are getting their essays checked.
John should be getting the new contract signed as quickly as possible.
I got the bill sent direct to the company.
We can also use 'have/get something done' in situations where something bad has happened to people or their possessions. This is not something they wanted to happen. We can also use the same expression when someone does something bad to us.
Brian had all his money stolen from his hotel bedroom.
We had our house damaged by a falling tree.
He got his nose broken playing rugby.
In all these sentences, we are more interested in the result of the activity than in the person or object that performs the activity.
As we all live in a busy world, we don't have the time (or skills) to do all the things that we need to. That's why we have a service industry that will help us get what need done.
A dry cleaner's is a place where you can have your suit cleaned.
A garage is a place where you can have your car repaired.
I had the electrician look at my broken light.
'X' NEEDS DOING
In the same way, the construction "X needs doing" has a passive meaning. The important thing in our minds is the person or thing that will experience the action.
The ceiling needs painting. (= the ceiling needs to be painted)
My hair needs cutting. (= my hair needs to be cut)