Only secondary if you are going to add fruit or dry hop. I even dry hop in the primary after fermentation is complete (because I'm lazy, and I don't want to risk the chance of oxidation).
Primary for 21-28 days, then secondary (if you choose to for 1-2 weeks)
+1 for the yeast "cleaning up" after themselves, allowing your beer to primary longer will give you a far superior end product, I know it can be agonizing, but let it sit in your primary fermenter for a month. Careful racking to bottling bucket or keg, and your beer will be clear.