Well, lets just say that it's uncommon for me to leave a post as it is after posting it.
It IS common however, for me to edit it about 3-10 times, to alter a slightly misspelt word (usually American-English to English-English), remove/add in a single word to fit grammar/logic better, add in a few bits onto the end of a sentence to explain it better...etcetc.
I do use the Preview button frequently (I especially love the auto-update with this feature as you type), however I still miss things. Badly. Especially L's, as my L key is iffy on my keyboard, and I can't be bothered to buy a new one just yet.
(EDIT
zoozilla said:
*EDIT*
Sorry for the crap post. I was drinking when I wrote this, so hopefully you can forgive these wretched words.
I too do this. Alcohol-induced randomness has frequently inundated my posts with pointless dithering and irrefutably pointless long words.
(EDIT 2

I had to replace a hell of a lot of missing L's there. Damn keyboard.