Ideally, an outdated answer should be edited. Aside from the reputation loss of deleted answers, there's two main problems.
Accepted answers can't be removed by ordinary means, and nobody but the OP of the question can change the accepted flag, so an inaccurate answer will remain at the top of the list for all time in most cases.
Unaccepted answers with high scores will remain near the top of the list, so they'll be more visible. It's better to edit the answer than to post a new answer that will be at the bottom of the list, possibly listed below inaccurate/less-accurate answers.
For an outdated answer edit, I recommend a direct edit for those with reputation, or a comment stating that the answer is outdated. I typically do edit outdated answers that get comments to that effect, and I know our other top users do as well. After all, we want accurate information to be at the top of the page for future visitors.
I don't mind deleting outdated answers, and obviously the reputation loss is insignificant in my case, but I could imagine someone who had just a single +10 answer with, say, 1k rep and just lost 10% of their total rep because of a deletion. It's not fair to wipe out someone else's work if it was fruitful at the time of posting. If you wouldn't do it to a 1k user, you shouldn't do it to a 100k user.
I rarely post answers on questions that have essentially correct or outdated answers. I prefer to edit or comment to get the information updated instead. I don't do what I do for the rep, or the MVP status, or whatever, I do it because I am passionate about Salesforce and when it succeeds, we all succeed to have better, more rewarding lives as a result.
I have deleted that answer, but I would invite people to consider how they would feel if the same thing happened to them.
