Just a note from my friend who is a Pops quality control tester - replace it once a year. It gets glazed and (relatively, for Pops) powdery. Once i found this out, when my cake of Pops "died" - after about 14 months of use - it felt like all of a sudden I needed a rehair. Got a new cake and was back in business. It's also recommended to keep the container snapped closed when not in use.
I've had the same Pops cake for almost 5 or 6 years now (I can't really remember exactly, but it's somewhere around there) and recently my bow's been not holding on to the stuff, and I've been thinking it's time for a rehair. I'll try getting new rosin and see if it does the trick (hopefully, as it is much cheaper this way
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