Everything in moderation" or "moderation in all things"?

Can you please tell me some idioms which express this idea: too much is always not good, or in other words, exceeding is bad, something like that…
Thanks in advance.

All I can think of is this:

It’s quality not quantity that counts/matters.

How about
“Everything in moderation” or “moderation in all things”?

Yes, right. I see it. Thanks a lot Tort and Mrs.Beesnees