I should say that the whole issue of when or whether to rack to secondary is very prone to debate. It used to be something you just had to do after 1-2 weeks always. Nowadays many people say to just leave it in the primary, then package. However, almost everyone agrees that if you want to ferment or condition for long periods (How long is long? Many weeks/months?) you should rack it off the yeast cake in the primary because eventually the yeast will start to die and decay, a process known as autolysis. Allegedly this is something you don't ever want to smell.
I've never used a secondary, but I brew fairly low gravity session ales and bottle after 2-3 weeks, so no chance of autolysis.