I use them when I buy singles, 5 packs, or samplers and write the exact name, date purchased (box code if known vs date purchased) and place purchased from in case I want to buy more. Example would be a fresh Padron maduro usually will not be as good as one that is over a year old. By labeling you will better know that type of information. Some sticks with labels of a fresher cigar I might pass over for a more mature one.
I also label sticks from PIF, passes, gifts, and when I consolidate boxes. Most times I include the person that sent me the stick and will send a PM to thank them later on too. I use the bands more and more, you will too.