The older brewing literature says to use the 1-2-3 method (1 week primary, 2 weeks secondary, 3 weeks bottle or keg). The newer literature says to use about 3-4 weeks in primary, and (unless fruiting or really high gravity) no secondary, then bottle until carbonated or keg. The quality of the beer six weeks from brew day handled the old way is much lower than the same period of time using the new approach. The reason the old way was stressed was that brewer's yeast used to reach the autolysis stage if left unattended for several weeks. This is no longer a problem unless you leave it for a really long time. If you use healthy yeast and follow good sanitation procedures, then leaving the brew in primary is actually beneficial, as the yeasts actually clean up fusels and other unpleasantness. One of the finest brews I made, a Trippel, was left in primary for 6 weeks.