I suppose that I can remember having my counting thing since I was quite young. I remember being afraid of the dark and to help myself go to sleep, I would count all letters and numbers around my room to try to help to to sleep.
I am now 33 and still do it, quite alot.
Seems we all have our differences. I count words and give each letter a value of one and try to get it to add up to an even number, has to be a even number. Also I count and draw the letters in my head and count to get an even number. I also focus on on a specific word (one that I might have heard) and count it up. I also will focus on objects and count the lines, like floorboards, the side a ceiling had, just about anything.
Good to know I am not alone. Any thoughts on how to stop it. Have tried over the years, seems to be increasing and do it more offent than I think I should. To make matters worse I am a chartered accountant (in Australia), I even work in an industry that would be able to help me, but too embarrased to ask.