Depends on the grout. You can still get the old kind or you can get the newer stuff that doesn't need sealing.

I've had grout for over thirty years in a white bath. ................no mold or mildew and I "scrub" nothing. I do clean routinely. If you are talking about a bath, you must use the VENTILATION word. Add "adequate". You can't get mold or mildew unless you have MOISTURE.

Jan, what are you cleaning with and how much ventilation do you have? My son and I are very chemically sensitive, so I'm worried about using strong chemicals. This has become an obsession with me!

Mold is worse for you than any cleaner. A good fan , a door to bath open as soon as you're out....

A good weekly cleaning. Use hydrogen peroxide , water, and drop or two of Dawn

Mold and mildew love moisture and bacteria.

What do I use'? Whatever is handy ! With a scrubbie !

Cement based grouts can be more problematic than others.

The single component grouts (Fusion Pro, as one example...there are others) will perform much better due to their composition. They eliminate blotchy or uneven coloration issues as well. Plus, no need to seal.

IMo ventilation is a must and then a squeegee for after every shower and once a week with vinegar water and a micro fiber cloth keeps all my showers squeaky clean with no chemicals.

Jan is absolutely correct; I tell that to clients all the time. And, yes, you can use the grout types from the pre mixed grouts all the way to the epoxy ones; just be sure that the installer is well versed in using them.

I have epoxy white grout in my shower and I wipe the walls down after each days worth of showers. Usually just me though. I have not had to "clean" my shower, (except the shower pan, which is cast iron) in a year. I have "cleaned" my shower probably 3 times in 5 years (except of course for the floor, which I don't wipe down after showers). I use a large auto detailing microfiber towel, one layer thick. It dries with in 12 hours. I always use a vent fan. I have enough space under my room door to account for makeup air so the vent can work.

Drying all the walls and caulking has worked for years for me. In my 3x5' shower with glass doors, it takes 70 seconds to wipe it all down along with the fixtures.