I use a very elegant cloth athletic tape labeling system for my beers. I make them on brew day, tearing off about 3/4" of tape with the beer name, date and OG printed poorly with an ink pen. They go on the fermenter(bucket lid), then they get kegging date and go on the keg, always just below the liquid post. When the keg goes into the serving fridge the fancy label moves to the fridge front above the tap handle.
I've been using the same roll of tape for about 5 years now. Well over 100 batches, many of which were 10 gals, so 2 labels. And before you get the idea I'm a cheap skate I want you to know this is the top of the line Mueller(no not @mullerbrau) athletic tape. I probably paid $4 for the roll.