Marble in the bathroom is a BAD idea - it's porous, so it stains easily. I went with a marble-look slab for my bathroom counter and have no complaints. More on reddit.com

Demo old vinyl and install new tile More on reddit.com

Cleaning marble floors with a mixture of water and vinegar is a common mistake that many people make, as vinegar is acidic and can damage the marble over time. The acidity of vinegar can etch the surface of the marble, causing it to become dull and lose its shine. Additionally, using too much water can seep into the marble and cause it to weaken or crack over time. It's important to use a pH-neutral cleaner specifically designed for marble to clean marble floors. These cleaners are gentle on the marble while effectively removing dirt and grime. Additionally, using a soft mop or cloth to clean the floors can help prevent scratching and damage to the marble surface. If your marble floors have become dull or damaged due to improper cleaning methods, seeking professional help is highly recommended. Professional marble restoration services have the expertise and specialized equipment to safely and effectively restore the shine and beauty of your marble floors. They can assess the condition of the marble, determine the best course of action, and provide a professional cleaning and polishing service to rejuvenate your floors. You can choose professional services like MARBLELIFE, Sir Grout, Grout Medic who offer expert services in marble restoration and maintenance. More on reddit.com

Be prepared to seal it at least once a year, and keep plenty of extra tiles for when someone inevitably drops something and cracks/chips/breaks/scratches them. Personally I hate marble and would never recommend it to anyone, for any room. It's typically very soft and requires high maintenance. I would prefer a good quality porcelain for the kitchen. But that's my opinion, and ultimately it's your house and you're the one that has to live with it. More on reddit.com