We use used + infinitive to talk about past habits.
- I used to smoke, but now I have stopped.
- He used to play football when he was a boy.
- There used to be a theatre at this corner years ago.
Used to -- has no present form. It has no progressive, perfect, infinitive or -ing forms either. To talk about present habits and states, we usually use the simple present tense.
- He smokes. (NOT He uses to smoke.)
Cases where used to -- is not used
Used to indicates a constant or frequent practice in the past, or the existence of something in the past. There is an idea that circumstances have changed. It is not used simply to say what happened at a past time, or how long it took, or how many times it happened.
- I went to Canada five times last year. (NOT I used to go to Canada five times last year.)
- I lived in Chennai for five years. (NOT I used to live in Chennai for five years.)
Be used to
If a person is used to something, he or she has experienced it before that it is no longer strange or new. Be used to can be followed by nouns or -ing forms (NOT infinitives).
- I am used to waiting for buses.
- I am not used to living in the city.
- I have lived in the city for five years now, so I am used to the noise.
Get used to + -ing
Get, become and grow can also be used before used to (-ing).
- Little by little, she became used to her new family.
- You will soon get used to living in the country.
Test your understanding of these rules with this would or used to grammar exercise.
Search the Dictionary of Practical English Usage