Differences between used to and would

I would like to know what the differences are between used to and would.
It is very difficult to understand because I cannot see the differences.
I asked this one, because I was told that you cannot used them for the same statements.
Thanks a lot in advance

"Would" can be used to describe repeated events in the past. "Used to" describes a past habit.

"Would" can be used when the repeated events took place within a short space of time:

"For three days he would try calling her every hour, but he never got an answer and soon gave up."

"Used to" is usually best for a longer period of time:

"He used to buy her flowers every Friday, right up to the day before he died."