Clear out old posts

Can someone tell me how to delete old posts so that people don't get sick of them??

I think they just drop off after a while. I've never deleted one.

I'm not sure if you can edit/delete your own posts, but trust me-  nobody gets tired of seeing them.  There are always new people who want to read as much about everyone else's experience as possible.  The things that you consider "old" are incredibly helpful to someone who is just starting the process.  :)