How do you know if a weakness is worth fixing vs ignoring?

There's a big difference between a weakness that actively breaks your business and one that just makes you uncomfortable.

If your writing is terrible, that hurts your sales copy so you have to improve it enough to get by. But trying to turn a C-grade skill into an A-grade skill usually takes way too much effort for a tiny payout. I've had much better results doubling down on my core strengths while keeping my weaknesses just non fatal.

Where do you draw the line between a flaw you need to fix and one you can safely live with?