There are no hard and fast rules really, but I tend to use a general rule of thumb of "Do the pictures actually need to be there, like are the pictures getting across any key information that enhances the setting, tone or action, or are you just using them as a pretty accompaniment to the text?" And usually, when the pictures are just there to look nice, but the narration is imparting all the info, you've got too much narration.
An example might be a panel of somebody being hugged with the narration, "she hugged me tightly". That narration would be pointless, in my opinion, and a big panel with a drawing that really captured that tight, emotional hug would be way more effective.
Or your protagonist walks down a street and the narration is like, "This city used to be the jewel of the north. Now it's fallen on hard times. Closed shops, thugs on corners." If you do the drawing well, you only actually need that first sentence. "This city used to be the jewel of the north" as we SEE this run down, grimy street with boarded up shops and "closing down sale!" posters and gangs in hoodies glaring at the protagonist from street corners, casually brandishing bats. If I wanted to remove the narration completely, I'd set it up so the protagonist or somebody describing the city as the "Jewel of the North", maybe show it in a flashback, or show an image of how it looked in a guidebook or a poster for contrast.
As a stylistic choice to make my current comic more cinematic or like watching a TV show, I chose to use pretty much no narration. At times it's tricky because I have to imply so much through just what people say, how they act and what my backgrounds tell you, but people have praised how immersive it makes the storytelling. So no narration is totally viable as an option, but I'm also a big fan of Homestuck, a comic with absolutely loads of narration; it's practically all narration with panels mostly used to support the jokes or action, sometimes ironically.
Basically, find a balance that works for you, but try to avoid using narration as a crutch. You'll make a more immersive and impactful visual story by working hard on backgrounds, poses or expressions.