what is the difference between " used to" and "would"?

[iconoclast]

rewboss's answer puts it in a nutshell. Contextually, however, we also tend to use 'would' when reminiscing about the good old days, e.g. My Grandda would always take a break and sit down in the windbreak for a smoke. first, he'd get out his plug of tobacco and chop off a few bits. Then he'd shred them in the palm of his hand and .....

[tareq10]

used to would are both used to talk about repeated actions and events

used to is only used to talk about repeated states and habits

e.g: I would /used to visit my friend every weekend. ( repeated action)
I used to be a teacher.( state in the past ) we can't use would
I used to smoke. ( habit)

[dasari]

good morning sir,
please requst for you what is the difference between will and shall ?please send me this difference

[alsooth]

1.used to.....refers to the things that you liked to do in the past.
For example--

John used to walk to school, but now he goes to school by bus.

2.The word "would" is not necessarily used as a past tense. You can simply use it in a "request."
For example---

Bill: Would you like to join me for dinner tomorrow night?
Tom: Yes, I 'd love to, but I'm afraid I can't.
Bill: How come?
Tom: I need to finish my history report. It's due this Friday.

[macanudo]

Another important difference between 'used to' and 'would' is that 'would' can only be used with past habits not past states:

Correct -> I used to own a Porsche before my company went bankrupt.
Not Correct ->I would own a Porsche before my company went bankrupt.

I just wrote a short article about this: Used to vs. Would
Be sure to check it out. I hope it helps.