First and foremost it really depends on your home and the layout. Here are a few tips from Nadine at Nadinestay.com
Pick one trim/baseboard color to be the main color throughout your home and pick another (painted or wood) to be an accent in 1 or 2 rooms. Whether you choose wood or white for the main color is entirely up to you, but in order to maintain some uniformity, I’d highly recommend picking one style/color for the majority of your home.
One thing I would not recommend is swapping trim colors from one space to the next in an open concept situation. So for example, I personally wouldn’t paint the living room trim white and leave the dining room wood if there’s little to no division between the rooms. Even a wide archway or an opening between the rooms is sometimes not enough to create a natural break and I often prefer connected spaces to match. But again, every home is different and some connected spaces (like in the photo above) can get away with a trim color change.
A natural place to play around with an accent trim color is in a separate space like a bathroom, bedroom, walk-in closet, or office. Having a door to separate one room from the next gives you a natural break to change trim colors. All the trim on the inside of the room is one color, and everything on the outside is another.
If you have a separate room that is clearly divided from its adjoining spaces but lacks a doorway in between (like a small opening), you could start the transition on the trim around the opening that leads into the “accent” room. The photo below is a perfect example of a natural transition from a white trim room to a wood trim room!
As far as doors goes, the “rules” are little more lackadaisical but generally speaking I like to keep the majority of my doors all one color. An accent door here and there is never out of the question and painting a door a different color on each side to match the room it faces isn’t unheard of!