Do you need commas with as needed?

You don't need a comma before "as needed" when it's used as a phrase describing frequency or quantity.

Here are some examples:

* Correct: Add water as needed.

* Correct: Take medication as needed.

* Correct: I go to the gym as needed.

However, if "as needed" is part of a longer phrase and the phrase itself needs a comma, then you'll need to use a comma.

Here's an example:

* Correct: I will go to the doctor as needed, but I don't think it's necessary at this time.

In this sentence, the comma is used to separate the two clauses, not specifically because of "as needed."