I have found that my beer peaks at about 5 or 6 weeks (all ales). I brew mostly basic styles, British Best, IPA, APA, Cream Ale, Porter, and the occassional American Wheat. All of these follow approximately the same time table. I'll keg after about 4 weeks, then after a week or two in the keg, the beer matures and then stays about the same until the keg runs dry. The biggest difference happens as the beer clears. From the first few glasses when the beer is cloudy, to about the 1/2 way point in the keg, the change is quite dramatic. Since the beer clears from the top down and the keg empties from the bottom up, the beer will keep getting clearer as the keg empties. The last few glasses are usually brilliantly clear.