https://screenrant.com/family-guy-lois-voice-alex-borstein-quit-when/

Family Guy star Alex Borstein comments on the conditions under which she would end her historic run as Lois, citing a barometer she has in place.

Frankly, the answer should have been "Never.", because I love Alex Borstein, having admired Lois Griffin and her voice since I started watching Family Guy in 2006.

"Ultimately, [Ms. Borstein] says, she would bow out when the jokes start to fizzle." Now that is going to be hard to tell because even at its worst, FG will continue to make me laugh, or at least chuckle, no matter what.

In the aftermath of the George Floyd protests that resulted in several minority animated characters being recast (including Cleveland), I have wondered if Tricia Takanawa (a recurring character of Japanese ancestry) will get recast by a different actor. Alex Borstein has stated (https://www.thedailybeast.com/family-guy-star-alex-borstein-is-ready-for-her-hbo-close-up) in the past that she was of Mongolian descent (different country, but still in Asia). I think Ms. Borstein's vocal delivery would be hard for another actor to replicate when she is gone from Family Guy.