Rewrite or delete?

Question

I was about to do a substantial rewrite of an answer I wrote but the rewrite would change well more than half the original answer (partially due to straying too far off topic). It occurred to me that deleting that answer and just writing a new one. What is the community view on this: delete and post new answer or just rewrite completely?

For reference my offending answer is in this question ( Does wearing a bicycle helmet make the cyclist safer? ) but I'm not asking here about the specifics there, just the general point of whether rewriting is better than deletion and replacement.

It looks to me like something that is likely to occur frequently so a nice definitive ruling would be good.

Answer 1

My rule of thumb is that: if it is a big enough change that the existing votes are no longer relevant and most of the up-voters would like an opportunity to reconsider their decision (you would expect), it's time for a new answer.

A similar ideas applies the comments, unless you are addressing them by making the change.

This still leaves a lot of wriggle room.

{I know I have made this recommendation somewhere before, but I haven't found it.}