Half a year after the CS is made. If lucky.
Not really kidding, as I have a bit of a problem when making characters.
When I make them, I treat them as unique individuals; and I make them so that they have elements of their character that can't really be duplicated. Each time I make a character I basically "generate" someone (something?) new. It's not always visible in the CS as I keep most of that stuff in my mind and use it when in actual RP.
The result of that thinking is that while I can shape words to fit my purpose (usually, I do sometimes end up lacking the right word) I can't draw worth a damn and images always have something off that doesn't connect with my mental image. And if something is off, I ditch the whole thing. Best I can do is find abstracts of my thoughts, and sometimes I can't find that much.
So ultimately, I end up going with a text description (although I'm not that great at those either, they at least somewhat reflect my mental image) and hope I someday find the right image for the character. Or get to be a lucky bastard and find someone who makes it to the particular theme of the character. Which has problems in and of itself (as it's not me making it) but it's a step up from an image designed with something else in mind entirely.