I recently found a good way to send a useful pointer to WndProc through the use of SetProp() for use throughout the entire program loop, but I never actually removed it because I never found a good place to. So I'm wondering bad the consequences are going to be if I don't use RemoveProp().
While I've never used these properties I would imagine the property list automatically get cleaned up when the associated window closes. Just to be on the safe side though I would be inclined to remove properties as part of the windows close code at the very least.
Humble people don't refer to themselves as humble (W.R.T. "IMHO".)