I often ask how big a top's cock is because I have been fooled before with artfully shot images that add 2" (not that I am accusing bigdick4u or Harry_Daddy_1963 of that). I don't have to get fucked by a huge cock every time, but I want to have a realistic idea of what I am getting. If there is nothing else in the image to provide a sense of scale then a cock pic tells me nothing other than the shape.
If I am just outside someone's age or body-type range, I will ask. That's because I am the age and size I claim to be. Lots of guys have already taken the liberty of shaving off 10 years and 25 pounds in their profile. I am asking if you might make an exception; many have and been happy they did.
I totally agree about people who are too drugged out to play.
I have only turned one cock away for being too big in 30 years of playing, and that was only when he wanted to fuck the second time after I was already sore. It was well over 12"