Quick question...

Do my characters all look the same? 

I am being serious here. I feel like I'm using the same base for all of my characters over, and over and over again, but I don't know, because I always color them in, giving them their identity. I try to make them all look different, but I don't think I am.

The reason I noticed this is because an artist I really like, (Whom I shall not name. They are wonderful and very good at what they draw.) posted a few pictures a while ago of line art and shading only, and when I first looked at the picture, I didn't know which character it was until I read the description. That doesn't mean it was bad though, it was a nice picture, I just didn't know of who at first.

So, if I were to do that to some of my characters, would you be able to tell ho they were, or am I using the same design in different colors over, and over, and over? And, on top of that, should I change that or just keep the designs I have? I am re-vamping a lot of my characters right now, so I can if I need to. 

Please answer this.