by Kale » Tue Apr 10, 2012 5:48 am
If you want to complete all the side quests available in LF1, you will need to be very thorough with the Thief Guild. The quest rewards you receive from them are time based, easily missable, and necessary to complete later quests in chapter 4.
You can still finish LF1 without ever visiting the Thief Guild though, and most of the chapter 4 quests have alternate solutions in LF2. It's not critical to ever visit the Thief Guild, but completionists will probably want to.