Having a good quality belt for concealed/open carry is very important. The first point of failure for people that are new to concealed/open carry usually happens to be the belt, or the lack thereof. Most people just assume they're going to wear the belt that they wear on a day to day basis, and some people wear no belt at all. Your belt is one of the most important parts of carrying concealed or open carry, and here's why:
*Your belt does two things while concealed or open carrying - it provides an attachment point for your holster, and it keeps the holster on a horizontal plane. Both of these are critical for keeping your firearm stable.
* A properly fastened and retentive belt also keeps the holster attached when you draw the firearm. Keep in mind that it's important to buy a belt that's custom fit to you, because a belt that is too loose, too thin, or not up to the task will flex and bend when you draw the gun, which could interfere with your draw.
* The belt is part of the concealment/open system. No belt, or too thin of a belt means a droopy buldge of a gun that moves when you move. There's nothing that screams "I'm carrying a gun" when concealed carrying, as much as a buldge that slaps your hip or leg everytime you walk or run. A good belt keeps the gun well secured and tight to your body.
* A good belt is critical to firearm retention, and is often the only thing holding your holster to your pants.