The whole question of racking to a secondary is a good one. There are no shortage of opinions on the subject, so I'll provide mine.

For most beers, a secondary fermentation is not necessary. In fact, simply racking a beer from a primary fermentation vessel to a second, clean vessel for the purposes of letting it settle out and finish isn't really a secondary fermentation anyway. Its more of a brighting process.

For a typical ale, I would leave it in the primary fermenter until it is cleared, which is usually about two weeks. From there you can bottle or keg the product.

For larger beers it may be necessary to rack from one vessel to another as the fermentation could take a bit longer. Typically the fermentation has completed, you will be transferring to an ageing tank or barrel - again, not really a second fermentation, it a conditioning stage.

For more complex fermentation schedules you may well be doing a true secondary fermentation. Two examples are fruit beers, or something like a quadruple which has sugars and yeast added in stages. For the fruit beers, you want to add the fruit toward the end of peak fermentation, let it settle down a bit then rack to a secondary to finish out and let the sediment settle.

For the quad, i actually add sugar at each racking. I get the beer of the trub, move it to a new vessel, and add sugars to restart the fermentation. I usually do this three or four times and at some point actually pitch a more alcohol tolerant yeast in to the mix.

So to summarize, for typical beers no secondary is needed. You can leave the beer in the primary for a month without any I'll effects. For some types of beers, the secondary fermentation or aging vessels are important parts of the flavor profile. You can't shortcut there.