Ah, November! The leaves have changed colors, the turkeys are shaking in their boots, Red Sox fans are preparing for next year, and all the shows on TV are new. It is, after all, that elusive time of the year – November sweeps.

Sweeps have been around about as long as TV has. While the viewers are guaranteed first-run episodes of their favorite shows, it’s not about entertainment at all. It’s about the economics of it all. November is when all of the ratings really count for something – money. Through a complex series of formulas, networks are able to determine how much they can charge for a 30-second advertisement in a given show.

The long and the short of it is that the more people who watch something, the more they can charge a company to advertise during it.

Pepsi might be able to pick up a 3-minute advertising spot for cheap during the 3 a.m. farm report, but how many viewers are they going to be reaching? But with 30 seconds during “Friends” or “CSI” they’ll be paying more, but they’ll be seen by the people who are likely to buy their product.

Every November, I get excited about all the new shows. The hour-long “Will & Grace,” the ripped from the headlines “Law & Order,” the season premiere of “The Simpsons.” It makes me forget about my current lack of cable.

But then I remember what it’s all about and I feel a little dirty, a little used. None of this is for my entertainment, it’s not to reward me as a faithful NBC viewer. No, it’s about me being part of the prime demographic – 18 to 34. It’s about my purchasing power. It’s about what 30 seconds of my time is worth to Pepsi and Toyota.

TV has always been about the money, though. “I Love Lucy” had commercial breaks where Lucille Ball and Desi Arnaz would stop to hawk Phillip Morris cigarettes. Now there’s a public outcry when the “American Idol” judges have everything but Coca-Cola bottle costumes.

There’s a choice to be made. Personally, I’d rather watch companies put on a dog-and-pony show to get my attention than have it slip easily in and out of the shows themselves. Besides, we all need to go to the bathroom sometime. I’d much rather miss an overzealous pet owner rushing home to his cat’s request for Meow Mix than a minute of interaction between Ray and Marie Barone.

The saying is that there’s no such thing as a free lunch. The same can be said of TV. You may not pay a monthly charge to watch NBC, CBS, ABC and Fox (and you probably aren’t watching WB and UPN anyway), but there’s an economy going on behind the scenes. There’s something chugging along that pays the sometimes outrageous salaries of our favorite characters.

So while there’s a tinge of betrayal I feel every November, I can also sleep easier knowing that this economy will ensure that “Inside Schwartz” won’t be on ever again. If it’s not a widely watched show, it’s not going to get the advertising money. And if it doesn’t pay, it doesn’t stay.