It depends on your story. I’ve read stories that were 5 episodes long that really seemed to drag and could have been condensed into 3 episodes. I’ve also read stories with 90+ episodes (my absolute favorites are Speak and Dripping Mascara) that each and every episode is engaging and makes me crave more. If you are just adding things for filler, it can become boring, but if every episode is interesting and works towards an overall goal, then length doesn’t matter.
Stories over 50 episodes that are amazing.
Speak by J. Miley (90)
Dripping Mascara by Genevive Marshall (132)
Pregnant By The Nerd by Trisha (60)
Dead Roses by Beeble Hope (53 and ongoing)