Sadly, I can't recall any specific time when thirteen actually paid off for me, but I've always felt that it was my number.
I have long rejected the traditional opinion that seven was a lucky number while thirteen was an unlucky one. Of course, my opinion on this matter was helped by the fact that I was born on the thirteenth day of the month.
For years, my dad told me I was born on a Friday the 13th, and so I'd held a very positive opinion of that day, contrary to the typical superstitions. When I learned to properly compute calendar events I learned that I was, in fact, born on a Thursday, which left me feeling a little disappointed. To this day, though, I feel like any Friday the 13th is my day, regardless of whether the month matches that of my birth. And when my birthday does fall on a Friday the 13th, I feel like it's an extra special treat.
I've never been particularly superstitious, and I wonder now whether my affinity for thirteen was a cause or a product of that.

I've always disliked the number 7 as well, in a not-terribly-serious kind of way. I pretty much let go of that iconoclastic-dislike when Emily was born, 7lb 14 ounces, on the 14th day of 1997, at 21:49. Now I'm just indifferent to 7. I'll give the 13th a nod, kinda like 666. Any number that can give people heebeejeebies is OK by me.
Never knew 7 was a lucky number, good info! :) As for 13 I had it as a favorite for some time striving to be unique, just because nobody else did. New favorite for some time is 6, the only transformable one digit. Eight is a secondary choice, upright eternity.