Heaven help you if you have a rigid grammarian reviewing your fundraising copy. It means you face annoyances and delays at best, weakened copy at worst.
How important is good grammar? Tom Ahern has a suggestion, at Will good grammar save us?:
... accurate, school-room-caliber, academy-approved writing will add almost, virtually, infinitesimally nothing to your sales.
But we hate mistakes. That's why I put "grammar errors" into three categories, each of which calls for a different response:
- Errors you should try not to make. Bone-headed things that are wrong, and not the better for being wrong. Sentences like, "He gave it to my wife and I." Or using apostrophes in plural words. Results-wise, getting it wrong or right makes little or no difference. So why be wrong?
- Correct grammar that makes you sound like a snob. These are complex sentences that don't sound natural, even though they're correct. Such as any sentences that uses the word whom. I'd rather get it wrong and sound like you belong to the same tribe as your donor than right and like you're putting on airs. Better yet, avoid the sentence structure that puts you in that position in the first place.
- Rules you should break because they make you less persuasive. There are a few of these, most of them not real grammar rules, like "don't start a sentence with a preposition." "Avoid contractions." "Don't split infinitives." "Avoid passive voice." You should freely do all those things. Obeying your grammar maven about those issues will cost you in revenue.