Several counselors I know recommend to their students that, all else being equal in terms of fit for a student, they include at least one "rolling admissions" school in their list. Rolling admissions schools don't wait until a single-date deadline has passed and then evaluate the whole batch of applications against one another. Rolling admissions means, basically, that as applications roll in to the admissions office, they are evaluated and given a thumbs up or thumbs down quickly, usually within two to six weeks of arrival at the admissions office.
This means two things for applicants. First, you don't have to wait until spring to hear whether or not you've been accepted, and if there is an offer of admission, you have at least one college in your pocket, and can therefore stop stressing quite so much about your other applications. Second, it means that if you are a qualified applicant and apply early in the cycle (August, September, October), you have a greater chance of admission than the superstar student who drags his feet. Why? Because once a rolling admission school reaches its capacity for acceptances, they're done. A great student who comes along late may just miss the boat.
The more popular the college (think University of Michigan), the more quickly the class fills up. On the flip side, less well-known colleges that use rolling admissions will keep their admissions open until they've reached capacity, and that could be much later than some of the application deadlines for regular decision colleges (usually January 1 through January 15). If a student self-describes as the next Einstein, and applies (unwisely) only to Harvard, Yale, and Princeton, that student may end up with three "We're sorry to inform you..." letters in April and then be saved by a rolling admissions college that is still accepting applications in late April or May.
The bottom line is this. If you have any rolling admissions colleges on your list, get to those applications right away. If you are feeling panicked that you aren't going to get in anywhere, perhaps it's time to find a rolling admissions school for which you are well qualified and would enjoy attending, and get that application in so you can buy yourself some peace of mind.