We use used to / didn't use to + infinitive to talk about past habits or repeated actions or situations / states which have changed.

Used to doesn't exist in the present tense. For present habits use usually + the present simple e.g. I usually walk to work. NOT I use to walk to work.

We can also use would (instead of used to) to refer to repeated actions in the past with action verbs (run, listen, study, cook, etc.). However, we can only use used to not would, for non-action verbs (be, need, know, like, etc.).

Alan didn't use to be so thin.

NOT Alan wouldn't be so thin.

With would, you must use a past time expression, or it must be already clear that you are talking about the past.

We can use past simple, often with an adverb of frequency, in the same way as used to and would to talk about repeated past actions.

I often got up / used to / get up / would get up early when I lived in Africa, to watch the sun rise.

Use be used to + gerund to talk about things you are accustomed to doing, or a new situation which is now familiar or less strange.

Use get used to + gerund to talk about a new situation which is becoming familiar or less strange.

The difference between be used to and get used to is exactly the same as the difference between be and get + adjective, e.g. It's dark and It's getting dark.

GU - 5B