Study materials
Two sentences about the old days. Both are correct, and the difference between them is easy to miss.
I used to live near the sea.
Every summer we would swim before breakfast.
Both structures describe what regularly happened in the past. But one of them can talk about states and the other only about actions. That is where most of the mistakes come from.
Used to: actions and states alike
This structure is the universal one. It suits a repeated action, a former state, and it nearly always hints at a contrast with the present.
I used to be shy.
We used to have a dog.
She used to walk to school.
The listener immediately hears the unspoken ending: and it is not like that now. That is why used to is so common in stories about childhood and about moving house.
Would: repeated actions only
Would sounds more literary and warmer, the way a memory does. But it carries two limits.
The first: it does not work with states. The verbs be, have, know and like are not used with would in this sense.
We would have a dog. → We used to have a dog.
The second: would needs a context already set. The reader has to know which period is meant first, and only then does would appear.
We spent every August at my grandmother's. She would get up at five and would bake bread.
Did wipes out the tense
In negatives and questions did appears, and it already carries the past tense itself. So used goes back to the form use.
I didn't use to like coffee.
Did you use to play an instrument?
Would behaves more simply here: the negative is wouldn't, and no helper is needed.
When the plain Past Simple is better
Both structures speak about regularity. If the event happened once, or if you do not need a contrast with the present, take the plain past tense.
We visited York in 2019.
I lived there for three years.
The mistakes everyone makes
The first is keeping used after did.
Did you used to smoke? → Did you use to smoke?
The second is taking would for a state.
I would be shy as a child. → I used to be shy as a child.
The third is opening a memory with would.
I would go to my grandmother every summer. → I used to go to my grandmother every summer.
All three are caught by two questions. Is this an action or a state? And is it already clear which period we are in?
Try it right now
Describe your childhood in English in three sentences. Open the first with used to and describe a state.
Then, once the period is established, add two sentences with would about what you did regularly. If you feel like starting the third with would be, go back to used to.