IMO the only time you punt any category is when you decide to give up on your league because I dont believe you can win any league punting a category.
I used to feel the same way. And I still refuse to actively punt a category. But I've changed my tune a bit on the viability of punting as a strategy.
The last league I played in, the guy who won punted saves.
This this year I'm in first place in my 12-team 5x5 by 10 points but in dead last in 2 categories -- W and BA. I'm not punting those by any means, but I might as well be. I'm absolutely cleaning up (tied for 3rd or better) in all other categories. It's a freak year.
I still don't like punting as a strategy. But I think to say that you can't win if you punt is misleading.
I think this quote from a TSN Fantasty writer is one of the better summaries on the topic:
I've heard experts and owners talk about "punting" the saves category. I strongly disagree. In a 12-team, 5x5 league, the winner usually ends up with about 90 category points, which is an average of fourth place in the 10 categories. Punting a category -- and likely taking a "1" for it -- means you must average about third place in the other nine. That's a pretty tall order. While you still can finish in the top three in the league, your goal is to win. And how bad can a single closer pick by the end of the fourth round screw up your strategy? You don't need to win the category, but try to avoid finishing last in it."