For me, It all started with my brother's copy of "X-Wing Collector Series Edition" when I was six. Me and my brother played the hell out of that game until the disc was unusable four years later. I never got around to replacing it.
So far, with a rough average of around five hours a day (two hours a day for the first two years, then eight hours a day the last year) for four years, approximately 7,000 hours, if my calculations are correct.
Rogue Squadron for the Nintendo 64 became an interest shortly after my introduction to X-Wing, and I still play it today. Because I never spent very much time on it, I have a total of 750 hours on that, thus a total of 7,750 hours.
For a period after that, the only flight sim I played was X-Wing Alliance, but never to the scale of X-Wing. 1,500 hours, total 9,250 hours.
I acquired First Eagles in March 2007, and WOV in November 2007. Total from both games: approximately 4,500 hours.
My total flight sim hours are:
13,750 hours well spent, over the course of ten years.
I hope to have a total of at least 100,000 hours by 2018.