I like to vary them because it could also show personality that isn't said :"o i don't have a comic yet but I plan to have my characters wear different outfits to also show a change of day as well.
Example i guess? This character has a methodological approach when it comes to his clothing. It's characterized by monochromes and blues/violets (just muted colors). He doesn't wear the same outfit most of the time but his pieces can be similar because of the combinations he used. Like in the second one (the most casual he's in), it doesn't have his usual waistcoat but the lighter blue part of the jacket has a v shape. It's formal-looking w/o looking very out of place in their world and w/o looking flashy.
There's also this girl https://toyhou.se/428577.-lianna-montgomery/gallery?key=Bd0p3bef8a56ZOU who I love to draw different outfits of. In her case it's more to show how wealthy her family is (with the patterns and jewelry). In her case too, it's probably one of my favorites because I can use the way she dresses in certain situations/with certain somebody as a contrast (like how she's covered up in social events and how shes willing to show part of her back/shoulders in another).
The only exception I can think of are when it comes to the gods in my story. I don't think they actually have a concept of time in their part of the world so they're just stuck in one or two outfits. The two that change outfits are to show departing influence from the main god.
edit: sorry for the rambly text haha, I just like clothes a lot ><