How often do you clear out your comments on Fluther?

First of all, I’m new to Fluther and am really enjoying the experience. (Okay, I’m very close to addicted, but that’s a different issue!) I’ve deleted some of the comments I’ve received, but kept a few as well. Especially those that were very informative. And, if someone were to send me a particularly nice comment, I would probably keep it. What about you? How long do you keep a comment and why? From a techinical viewpoint, is there a reason it might be better to clear out your comments?