Maybe you're working out regularly, and that's awesome . . . but don't you get bored? If your routine feels dull, chances are your body's gotten used to it too, and that'll impact your fitness level.
Keep it fresh with a jar full of "workout wildcards." Write down 20 different routines on slips of paper (get ideas from magazines if you like) and put 'em in a jar. Pull one from the jar anytime things are getting, shall we say . . . too routine!