After nine seasons and 200 episodes, Grey's Anatomy is showing no signs of slowing down. Season nine of the Shonda Rhimes medical series averaged a 4.1 rating among the key adults 18-to-49 demo, making it ABC's top scripted drama in the advertiser-coveted metric. The Ellen Pompeo- and Patrick Dempsey-led ensemble also ranked as the 10th-most-watched program overall in the demo and second-highest-rated overall, trailing only Fox's The Following.

As the show unspools its 10th season, with episode 200 airing Oct. 10 at 9 p.m., creator Rhimes will be tasked with writing out one of the show's most beloved characters, when Sandra Oh, who plays Cristina Yang, exits after the season finale. The producer behind ABC's hit Scandal also will be weighing uncertain futures for her two lead characters as Pompeo's and Dempsey's contracts are set to expire.

Rhimes, 43, a mother of three, tells THR about the challenges of rebooting Grey's every year, the importance of a cast who wants to be there and whether she'd do a second spinoff.

Over the course of the series, what has been your biggest challenge?

Keeping it fresh every season. The only way the show remains interesting to me creatively is if we're reinventing it at the beginning of every season. To find ways to do that as many times as we have has been a challenge.

What's been the most valuable lesson you've learned doing that?

Don't be afraid to tell a story. Be fearless, don't be afraid of the critics or the critics in your head. The hard stories are often the most interesting. I learned how to write television and run a show on Grey's Anatomy. I've made all my mistakes and learned a lot of valuable lessons here.

How did your experience on Grey's help to launch Scandal?

I learned on Grey's that you don't want anybody on your show that doesn't want to be there. I wanted Scandal to be a place where everyone that you're working with was a lovely, giving person who was as excited about this as we all were. There's no competition, no jealousy and no drama; it's just a family, and that's what Grey's is now.