USED TO and WOULD are used to describe events, situations or actions that happened in the past, but don’t happen anymore.
However, there is a very significant difference between USED TO and WOULD.
1. WOULD is used when we establish the past time frame before the word would appear.
- When I was a child, I would watch cartoons with my dad in the mornings.
- When I was a student, I would read books in the library every Friday.
If the time frame is established after, USED TO can be used.
- I used to watch cartoons with my dad in the mornings, when I was a child.
- I used to read books in the library every Friday, when I was a student.
2. WOULD is not used with stative verbs (verbs that describe a state of being), such as be, understand, feel or love.
- When I was a kid, I used to feel happier.
- When I was a kid, I would feel happier.
3. We cannot use WOULD when we want to talk about past state. We have to use USED TO!
- I used to live in Chicago, when I was a kid.
- I would live in Chicago, when I was a kid.
So, the use of WOULD is more limited than USED TO.
Be careful when you choose which one to use. If you are really unsure, use USED TO.