It resets every time you leave combat. If you tell them to hold while out of combat they will. However, if you enter combat (which in inquisition only requires you to use any skill or attack.. even if there is nothing around) and then leave it again (you put your weapons away) all commands are cleared. If you tell them to hold while in combat, then they will hold until you leave combat. There is also a maximum range you can run from your party before the game teleports them to you.
There is also a random bug where your commands just clear for no apparent reason on 1 or more characters.
