I usually leave my beer in primary for 2-4 weeks. Once i left it in there for 5 weeks and it was fine. Essentially just let the beer ferment out and then the yeast kind of clean things up for a week or two and then let the beer settle out. No need to transfer to secondary. Also some folks will tell you you have to get it off the yeast after 2 weeks to avoid off flavors but that was proven unnecessary.
This might be the beer talking....but I really love beer!