I've unfortunately lived in too many houses where mold becomes a problem. It's never my fault, it's always been because the house is old/doesn't have proper damp proofing/cheap paint was used, or no damp proofing applied on exterior walls. I clean it, of course, so I'm not literally living in a house with moldy walls, and I keep the house as dry and ventilated as possible. But in certain climates it's nearly inevitable to get mold during winter or the humid season unless the house is very well built and modern.
The worst, and again very common, is when the paint is so cheap it can't be cleaned easily - when you use anything that can actually clean the mold (soapy water + a bit of vinegar is my preference, but baking soda, very weak bleach solution, or commercial mold cleaners) it also destroys the paint.
The worst, and again very common, is when the paint is so cheap it can't be cleaned easily - when you use anything that can actually clean the mold (soapy water + a bit of vinegar is my preference, but baking soda, very weak bleach solution, or commercial mold cleaners) it also destroys the paint.