The next fastpass availability time is printed on you ticket, very small on the bottom. At MGM I went to lights motor action and got fastpasses at 9:00 and I obtained 4 more fastpassses at 9:08 for TOT, 30 mintes later I got 4 more for Rockin roller coaster, so I was carrying around 12 fastpasses by 10 am. Also, if you don't make it back in your time frame window, printed on the ticket, you can use it anytime later that day.... a cast member gave us fastpassess with expired window times and told us we could use them later and we did.