When to Hyphenate

Q:

Dear Grammer Cop,

I work at a vet clinic and we have two cats to give away. We are putting up a sign, saying that we have two "five month" old cats which need homes. Would there be a hyphen between "five month?"

--Concerned

A:

Dear Concerned,

It's really a matter of personal preference in this case. Hyphens are generally used in instances like this to group closely related terms, and I think that certainly applies, so I'd use the hyphen. You might even consider "five-month-old". Again, it's whatever looks best to you.

Hope this helps!