For me, it depends on the character and the situation. A lot of the characters have uniforms so those typically stay the same. I change the outfits frequently on the main character Maddie because I feel it highlights her personality and wealthy lifestyle. On my characters that wear suits, I might change details like the color of the collared shirt or tie. I think a certain level of consistency helps the reader remember who is who, but switching it up keeps it more realistic and can reveal personality traits! i.e. I don't think one of my characters would wear a suit when taking his daughter to tumbling time, but he would definitely wear a suit at work to remain professional.
There are also situations where characters in suits might take off their blazer, untie their tie, or unbutton some of the top buttons of their shirts. I don't know if that counts as varying the outfits, but I think it helps illustrate how they're feeling at the moment.