It depends on what you want to listen to, and what scanner model you are using.
For example, if you're wanting to monitor Lexington County agencies, you might want to program the Lexington simulcast site to ensure you receive all of their transmissions.
If you're using something other than an SDS-100 or 200, you may be experiencing simulcast distortion monitoring the Richland Simulcast site. If you're in range of the Harbison site toward the north of Columbia, you might find that your decode quality improves.
However, if you only want to listen to Columbia City, Richland County and state agencies, you're probably hearing everything you want via the Richland County simulcast site. And if your decode quality is good, then I'd leave well enough alone.
