I think trades should expire in 30 real days(30, 24hr periods aka real world days) not 30 long-in days(days in which the player is logged in). Almost all of the trade's I've looked at for lions I want, that don't have a buy out, the owner hasn't logged in 3+ months which is kind of annoying fishing through them to find lions I can buy or make an offer on.

Example:
I make a trade on Sept, 6 2015(day 1) it would expire after Oct 5th, 2015(day 30).

(Edited a few times for clarification)