What goes around comes around
Meaning #1:
The way that you behave now will affect how you are treated in the future, even though this may not happen for a long time. Life has a funny way of giving back what you put in.
Example:
- I have helped friends out in the past and I don't really mind — what goes around comes around.
- I believe that what goes around comes around and that one day he will pay for the misery he has caused.
Meaning #2:
Something that is not successful or fashionable now will be successful or fashionable again in the future, or something that has happened in the past will happen again in the future.
Example:
- We have every chance of becoming a great team again. What goes around comes around.
- If I have learned one thing in life it is that history repeats itself, that what goes around comes around.
- https://dictionary.cambridge.org/dictionary/english/what-goes-around-comes-around, with editing
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Ha, "Déjà Vu"!
My impression on meaning #1：种瓜得瓜 种豆得豆 。
"What goes around comes around" because “you reap what you sow", and "revenge is better served cold" if it might not be clear for a short while.
For meaning #2：三十年河东 三十年河西, with a pseudo poem by 西岛 
:
The sun rises every morning
The moon comes after the sun
No winter lasts forever
No spring skips its turn
Today will become yesterday
Tomorrow stays tomorrow
Everything goes in a circle
What goes around comes around
Enjoy your Wednesday wherever you are!
