Professionally, you're being hired as a day player, which means you'll get paid a certain amount for each day worked, probably scale plus 10. Your credit will appear in the end titles on a shared card, and your dressing room will be in a honeywagon. Artistically, the part won't be substantial. You'll provide exposition, or you might die early so David Caruso can spend the rest of the hour tracking down your killer.
Having a few co-stars on your résumé is helpful if you're trying to find a decent agent. Those credits show that you know how to audition and, more important, that you understand how a professional set works. This makes you more attractive as a possible client.
Now here's the rub. If you want a long-term career doing challenging work while making a decent living, you'll need to start passing on those small co-stars so you can make the jump to guest-star roles. The question is, when? Where's the line?
In my opinion, you shouldn't do more than five co-stars. That's not a hard rule. It's just a number I made up. A few more aren't going to hurt you. But if you go beyond that, agents and casting directors will start thinking of you as a day player and nothing more.
Over the years, I've helped many clients transition from co-stars to guest stars. All they had to do was learn how to say no. Actors spend their whole lives trying to score auditions, so it's hard to pass, but that's what my clients had to do. At first the casting directors were confused—even upset—but after a while they got the point, and those actors started getting shots at those meaty guest-star roles.
Other clients refused to listen. They didn't have the balls to pass. Instead, they kept jumping back and forth between co-stars and guest stars, sending mixed signals to the casting community. As a result, their résumés ended up looking scattered, with no clear direction. We had to drop those actors so they could pursue careers as day players somewhere else. (At my agency, you rise to our level. We don't lower ourselves to yours.)
Now, don't get me wrong. Maybe you don't care about any of this. Maybe you're fine doing small parts here and there. That's cool. It's your life. Someone has to play Waiter No. 1. But I'd like to think you want more.
So let's say you've taken my advice and you're finally booking guest stars. What does that get you? Professionally, you're making more money. One-day guest stars get paid much better than one-day co-stars. And if you're boarded to work more than one day, they have to buy you for the entire episode. In other words, a one-hour show takes eight days to shoot, and if your part works two days, you'll get paid for all eight. That's called "top of show," and depending on the union, it's just over $7,200. Not bad, huh?
Also, your credit will be up front in the main titles and you'll be chilling in a much larger dressing room. Artistically, the roles are better too. They're crucial to the plot, so you'll get impressive footage for your reel, which in turn will help you score more guest-star auditions. Ah, the cycle of life….
And here's another big plus. Would you like to be a rich series regular one day? Well, a hundred co-stars on your résumé won't get you there, but 10 guest stars might.
Remember, it's not enough to be good when you dream of being great.