There are several variables related to this.
JosterLeave
JosterPaid (Global Timer)
JosterReturn (Global Timer)
When the game says "The quartermaster awaits you in the guild for Renal's due.", JosterReturn is set to 6 in-game days (43200 seconds real time), JosterPaid is set to 5 in-game days (36000 seconds real time), and JosterLeave is set to 2.
So, after you see this notification, if you wait 4 days then pay Joster, it means he will show up again only 2 days later. This makes it feel like he shows up too often. Especially if you rest too much, because the timer is in-game time.
JosterLeave is set to 2 when the game notifies you it is time to pay, set to 1 when you pay Joster and he leaves. If you don't pay him within 5 days of this notification, the timer JosterPaid will expire and JosterLeave is not 1, and you will lose the guild, UNLESS you're in chapter 4, 5, or 7.
When you enter the guild area (AR0322), Joster will be spawned if JosterLeave is 2 and you have not lost the guild yet (PGFailed = 0).
There you have it.
PS: naturally, all this is from vanilla, unmodded game.
Post edited September 08, 2019 by amazingchestahead