I would say that you should use it only for remove medications and if your water clarity is not good. Carbon will clear up a lot of yellowness that your water may have. If you think your water is clear enough for your liking, then I would waste my time.
I am now going to limit the use of carbon even in removing medications. I recently almost killed my Emperor Angel that was in quarantine with carbon. I had the carbon in a bag where water could gently flow over it. I had it in the tank for almost 2 weeks when it started to disintegrate and filled the tank with carbon powder. There was powder all over everything and it cause cloudy and then fraying and receding fins on my Emperor. I tried to do a couple big water changes after removing the carbon, but the fins kept getting worse so I threw the Angel into my main tank. He has been recovering some so far from the carbon, but has a long ways to go. I don't know if I have a bad batch of carbon or what the deal is, but it sure scared me.
I agree with the above...the only media I will be using in my 125g will be biopellets...and purigen if I think I can get away with using another media in correlation with biopellets.