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Re-check the length of the spring and adjust, if necessary.

or

Re-check the length of the spring and adjust if necessary.

--> Comma or no comma before "if necessary"?
--> Can anyone provide the grammatical rules for this?
--> This sentence does not look like a normal conditional sentence to me, so I am not sure whether the traditional punctuation rule for conditional sentences applies here.

Thanks for any help on this matter.
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I think that comma is optional, but the sentence is better without it, and there is a different comma missing. "If necessary" can be thought of as parenthetical or not as you choose, necessitating or obviating the comma, but it looks fussy.

You should put a comma between the two independent clauses, though: "Re-check the length of the spring, and adjust if necessary."
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Dear enoon,

Thank you. You are correct.

If there is no comma between the two independent clauses, the "if necessary" would apply to both of them, which should not be the case here. "if necessary" must only refer to "adjust".
That is not the reason for the comma. When two independent clauses are joined by "and", put a comma before "and". This is Commas 101.

"If necessary" applies only to the nearest clause, and it does not make sense to say that you should only check the spring if necessary, because you would not know whether or not it had been necessary to check it until after you had checked it.
"Adjust, if necessary" is an independent clause?
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In the sentence below, is a comma necessary following "as needed" at the end of the sentence?

  • Television crews and reporters are prohibited from using cameras inside the hospital, or speaking with staff, visitors, or patients without management approval. Contact Protection, the Legal Department or Facility Administrator, as needed.
teal file 254is a comma necessary following "as needed" at the end of the sentence? Contact Protection, the Legal Department or Facility Administrator, as needed.

No.

I disagree with you experts. What if you put "as necessary" at the beginning of the sentence. You would defintely add the comma. Right? Then I say, it belongs there when added to the end of the statement for the same reason. It is a conditional statement.

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