I had a question from Dane, who watched one of the videos and was sharp-eyed enough to notice that some of my frames have dates written on the top bars. The question was, "What's the purpose of that?"
I dated those frames so I'd know, a few years down the line,how long they've been in use. At some point it's considered a good idea to replace "black comb" with new foundation, just as a hedge against disease.
Some people recommend switching out old foundation/comb every 3 or 4 years, but others don't change them out at all. I'm going to play it by ear, and see if I can establish any kind of guideline of my own.
I don't do this with all my frames, by the way. The ones on the video just so happened to be ones I'm going to be experimenting with. In case you want to look here's the video Dane was referring to.
Thanks for the question, Dane!