Many beers include flavors or aromas that will vanish over time. IPAs are one example, many different kinds of wheat beers are another. Leaving an IPA in a secondary vessel to age for too long will result in a maltier, more oxydized beer, and a wheat that's actually TOO old just won't taste good.
Red ales - like the one you say you have in secondary - won't be harmed by an extra week of conditioning. They have lots of malty flavors that need time to meld, and (comparatively) few alpha-acids to volatilize off. Just remember that you need to be disciplined about your timeline for SOME beers, and plan appropriately!