Originally Posted by Puddings

...[D]o those premium tickets for gatcha expire or i can save them for later?

Premium tickets (3*+) Do not expire
4* Tickets do not expire
5* Tickets do not expire
5*+ Tickets can expire
6* Tickets should be used immediately (In the slim chance these do expire, are you really willing to risk losing out on a rainbow?)
5* and 6* Exchange Tickets should be used as soon as possible as they will be removed from your inventory at a set date.