should and would

There are really three different verbs

1. Should

This verb (I should/ you should/ he should etc) is used to talk about obligation, and in some other ways.

2. Would

This verb (I would/ you would/ he would etc) can be used to talk about past habits, and to make polite request

3. Should/ Would

This verb - the conditional auxiliary - has the following forms:

I should/ would
you would
he/she/it would
we should/would
they would