Used to and Would

• used to / would + infinitive
  Example: I used to / would smoke.
• did not + use to + infinitive
  Example: I did't use to smoke.
• did ... use to + infinitive?
  Example: did you use to smoke?

• We use used to + infinitive or would + infinitive to describe repeated actions in the past:
  • I used to keep the windows closed when I first moved in. (but I stopped doing this)
  • I would leave the windows open whenever I was at home.

• We use used to + infinitive to describe past states that are usually no longer true:
  • We used to live in London when I was a kid. (but we don’t now: not We would live in London when I was a kid.)

• We do not use used to to refer to specific restricted periods in the past or saying how long it took or how many times:
  • I lived in New York City for ten years. (not I used to live in New York City for ten years.)
  • I went went to London twice when I was young. (not I used to go to London twice when I was young.)
  • Note: we do not use would with state verbs.