EXAMPLES:

(a) I used to live in Washington, D.C.
(b) Everyday I would go jogging past all the famous monuments.
(c) No matter how hot or cold it was, I would run around the Tidal Basin and along the Mall.

** Habits and regular activities in the past are described by using used to and would.
Used to is often used in the first sentence to establish the topic.
Would is used in other sentences to supply the details.

(d) When l was a child I would wait at the bus stop for my father to come home.
(e) When I was a child I used to wait at the bus stop.

** Habitual activities can be expressed by both would and used to.

(f) When I was a child I used to have lots of toys.
(g) When I was a child I had lots of toys.
(h) NOT: When I was a child I would have lots of toys.

** Habitual states must be expressed by used to or simple past tense. We do not use would.

LARSEN-FREEMAN, Diane. Grammar Dimensions

BUT

If it is not a repeated action of the past neither used to nor would can be used:

In July 2001 I used to travel to Canada. (This sentence is WRONG.)
In July 2001 I traveled to Canada!