An article by Tim Bowen explaining the difference between 'used to' and 'would' when talking about the past.
Used to and Would
1. Both used to and would can be used to describe repeated actions in the past. They are virtually interchangeable, but from the point of view of style, it could be argued that would is slightly more formal, more ‘bookish’ and can convey the idea that the speaker is reminiscing about the past. It is often used in writing to talk about the past in a misty-eyed, sentimental way. For example:
When I was young I used to go fishing.
I used to have a cat.
My grandfather would always smoke his pipe after dinner.
People would get very angry when the tax-collector came to town.
In those days people would draw water from the village well.
When I was a child I would wake up to the sound of birds singing.
2. Neither used to nor would can be used to refer to single actions in the past. For example, it would not be possible to use either form in this sentence:
In 1992 I moved from London to Leeds.
3. Used to can also be used to describe past states, with verbs such as be, have and live. For example:
I used to live in France.
He used to have a beard.
This building used to be a hotel.
4. Would cannot normally be used in such sentences, unless the state is repeated and qualified by an adverb such as often. For example:
When I was a student, I would often have a beard.
This suggests that the state was repeated several times over a period of years, but it is a highly restricted use of would.
5. Used to cannot be used to refer to specific restricted periods in the past. For example:
In September 1991 I used to live in Paris.
This sentence is incorrect and the past simple should be used.
Perhaps the best practical advice to the questioner is that used to is generally correct when referring to repeated actions in the past and to past states, whereas would is often inappropriate. Would in this sense is possibly best left to the written language.