The use of used to do is explained here. However, used to has another meaning, it can be used as an adjective and we use it to talk about things that have become familiar, and are no longer strange or new.
Used to usually comes after verbs such as be, get or become.
You can also say that someone is used to doing something.
I was asked on Pal Talk recently how to use used to and would.
If we say something used to happen we are talking about repeated events and actions in the past, usually things that happened a long time ago and are now finished.
To express this we can use either used to or would.
Of course I no longer play with dolls!
If you want to talk about repeated states or habits in the past, you must use used to, you can not use would:
You should use 'use to' without a d in sentences when it follows 'did' or 'didn't' (don't worry too much about this because lots of people get it wrong).
The question form is „Did you use to…?'. When asking a closed question you put did/didn't in front of the subject followed byuse to, you cannot use would.
Also when asking questions about states in the past you cannot use would.
. In the negative you cannot use would without a change in meaning.
If I said I wouldn't play with my dolls. It would mean I refused to play with my dolls.
If I said we wouldn't go out much. It would mean we refused to go out much.
!Note - The general rule is when there is did or didn't in the sentence, we say use to (without d) when there is no did or didn't in the sentence, we say used to (with d).
There is also a difference between "used to do something and to be used to something".