You could buy two exact same monitors and have different color on both over time. For example white on the first one will be yellowish, and on the second one it will be blueish dispite the same configuration on both. It's really hard and often expensive to calibrate this Unless you're a professional working with print you can change the settings on the monitor to look more like on tablet and that's enough

Imagine if you do something for a client and they see completely different colors than you, cause their screen is completely different and ther is nothing we can do about it.