I have an app to do the first on it's own whenever junk data gets over a specific size. I clean the actual phone only when stuff gets under the screen protector.
Practically every day. I take public transportation so when I get home I'll use a disinfectant wipe on it to kill any germs. It's a habit that's stuck with me since the pandemic and it's just nice to have a clean phone.
Honestly, once every 3-4 months I take the case out and give it a wipe with the help of isopropyl alcohol. I thought I was dirty, but I'm seeing that I'm one of the cleaner people.
At random times, honestly. Usually when I am bored and get the phone out of the case just to see how dirty the sides and back are. Along with that, I clean the display as well, though with only a fiber clothing.
Maybe twice a month I’ll get that ADD tick to take my case off and deep clean the entire phone, charging port included. That part specifically reminds me of picking belly-button lint.
If it’s dirty, I wipe it with a microfiber cloth. I don’t wash it or anything, after all I’m the only one touching it and I wash hands and keep regular hygiene. If I’d be working in a hospital or other place where increased hygiene would be necessary, I’d do it more often. When I still work in the kitchen, I just left my phone in my locker, washed my hands before my shift (and during of course) and it’s not realy a big deal.
I'll be significantly cleaner than average I expect... I don't like cases, but a long time ago, circa when shiny black plastic was making its way in to touch screen phone design for the first time, a friend and I discovered if you keep your phone in a microfiber bag (like some sunglasses come with, particularly Oakleys we bought together at the time) it effectively cleans itself in your pocket. I still do, and I cycle those out and clean the bag once a year or so, or if it falls on the ground or gets something spilled on it. I have more now from different sets of sunglasses, laser goggles, etc.
I also happen to work in a clean room where you're expected to wipe anything you bring in, including phone, laptop, etc., with isopropanol-soaked wipes before entering so that's like disinfecting and taking off the oil every day or every other day.
No one else I know ever cleans their phone beyond wiping it with a shirt or something when the oil & smudges becomes too noticeable.
I just put it in my PhoneSoap when I shower and wipe fingerprint oil off when it's done. I'll clean the charging port and between the case every 2-3 months or if I notice a buildup around the camera cutouts.
A few times a month with a Clorox wipe. Should honestly do that daily seeing as though I use it in the shitter. Also using it while in public, germy hands then touching the phone - yea, would probably be wise if I Clorox wiped it daily. Oh well!