Ditto. Bought 5 tickets for my trip last April, arrived in a week, and used them with no problem.
And I second ngmaui's recommendation to scan the backs, or at least copy down the numbers. I did both, and had a piece of paper in my wallet with the numbers. It came in handy when, after the eleventy millionth ride on Splash Mountain (my 5 yo granddaughter loved it), we got so soaked that the water got through the tickets. The fastpass machines (at Splash Mountain, of course) would no longer accept them. So I hoofed it back to Guest Services at Main Street to get them replaced. The tickets were so soaked that the CM couldn't read the numbers. She was so impressed when I whipped out the piece of paper from my wallet with the ticket numbers on them. She commented that it was a great idea. With those numbers, she replaced the tickets in about 1 minute flat.
-Bob