This thread is opened because of two items I recently ran into:
1. Bakersdozen reported that she began using a "sharpie " (permanent marker) to write on her frames the year in which they were built.
2. In the process of repairing and painting some old roofs of my hives I came across pencil writing from at least fifteen years ago, when I recorded information about assorted things I had done with the hives beneath them such as: dates of inspection, addition or removal of honey frames and even simple items such as "QC" (=queen seen), etc. I had totally forgotten about those records but here they were, many years later, clear and visible for anyone who took the trouble to look.
Writing on a roof can have many advantages--simplicity, easy accessibility, and even a sort of permanence. I had written with a "carpenter's pencil" and the markings withstood the test of time in spite of exposure to the elements.
Only one drawback---don't switch the roofs of your hives if you decide to try it.