To put all your eggs in one basket

Meaning that you rely on one particular course of action not considering other possibilities first.
I have considered changing my job, but I don’t think I should put all my eggs in one basket.
This person thinks that a change of job might be a good thing, but it also involves a risk that might be difficult to change back if things don’t turn out as well as they had expected.
Picture from Daku 121
To cry over spilt milk

Meaning that a person is wasting their time worrying about something bad that has happened but cannot be changed.
It’s no use crying about spilt milk. Why don’t you speak to him about it?
Not to have a bean

To be without money.
I’m sorry. I can’t lend you any money. I haven’t got a bean!
To not know beans about something
Meaning that somebody doesn’t know anything about a particular subject.
I don’t know beans about art.
Don’t count your chickens (before they are hatched)

Meaning that you shouldn’t count on something good happening without considering that something may go wrong first.
She wanted to buy a new car in case she got the job, but I told her not to count her chickens before they hatched.