put all your eggs in one basket
depend on one person or plan of action for your success
I know you're confident about getting that job but I don't think you should put all your eggs in one basket. Why don't you apply for a few more, just in case?
take someone under your wing
protect and take care for someone
When my niece came to live in London she was a bit lonely so I took her under my wing till she settled in and made new friends at work.
be no spring chicken
be no longer young
He might dye his hair and wear the latest styles but he's no spring chicken and he's not fooling me!
a nest egg
a sum of money that you have saved or kept for a special purpose (for example, for when you retire)
We've saved a little bit every month since my daughter was born and now that she's ready to go off to university our nest egg will help pay for her education.
be as free as a bird
completely free to do as you want
Now that she's retired she's as free as a bird and is already planning her round-the-world cruise.