Regardless of how you argue it LCD screens are rated by contrast ratios much like projectors are. this dictates how true your color matching can actually be.

There are several ways to calibrate your monitor.

You can do it manually using any number of online sources to help you. this is the least accurate of ways but it gets you near the ballpark.

You can get programs that do it according to monitor brand and comp specs. These will get you to the gate.

Then you have "Spider" type calibrators which use a combo of software and hardware to calibrate the monitor and builds a profile that loads every time you fire up your comp. Spendy but these are the best.

A monitor should be re-calibrated at least once every two weeks for maximum performance. I tend to run mine once a week because I have an older monitor I bought used and want to be sure it is spot on. My laptop I don't bother with anymore, it just annoys me to worry about it.