about gareth
supposedly if you go directly to his house you can save his family from being killed. if you do other things before finding him at his home, his parents will already be dead and the quest unfolds differently. i've never actually done this since i've never gone to his parents' home first thing, but i've read about people doing it on this forum
this is also not really time related but if you rescue gareth during act 1 before finding the seekers' camp and healing the injured warriors, upon reaching the camp you'll find said warriors all dead (if you find the camp first, you can heal the warriors for a couple of rewards, but i believe these can be looted off their bodies). more to do with the way quests are completed than time
other than that, there's nothing i know of
