Quote Originally Posted by Amane Ito View Post
Completing seats upgrades is better than upgrading stadium directly, it decreases cost and build time of next stadium upgrade equal to the seat upgrade cost, so it is same cost and number of days required for the next stadium but you got to use these seats earlier if you upgrade the seats instead. If you build the stadium you have to wait for it to complete before the new seats could be used.
Everything he said,

check out my upgrading your seats guide in my sig.