Best is to, at LEAST, squeege the walls and floors after use. BEST is to dry off and use the towell to dry off the walls and floors and then leave the door open for a while and/or use a fan. If you do this...it will last forever. By the looks of the drain, you have a Schluter Kerdi installation. That goes a long ways toward a quickly draining installation.....

Thanks!!

«Live Clean Today» know how to do any cleaning. Maybe they`ll give some advises.

Also, you want to use a neutral PH cleaner for anything you might do there....

you'll want to test your water pH. Marble is typically between 7pH and 10pH. Lower pH will etch your stone. Higher pH water generally is a result of water hardness-i.e. calcium- which means you will get build up. A whole house filter can help and also using neutral pH cleaners regularly as described above by others. Again, neutral pH is always relative to the type of stone. DO NOT skip on applying sealer every year and I'd even recommend twice a year. Eventually you will need to polish at some point, but removing etching costs a lot more when polishing than just doing a top polish to bring back the shine, so take care of the stone.
Feel free to call AAAStonePro.com, IG:@AAAStonePro, if you have anymore questions or when you do need a polish further down the road. I'm always free just to educate other on the proper care methods and treatments.