IKIER K1 - how often do I need to clean the lens?

I think it very much depends on the use. Some materials and processes are extremely dirty while others are quite clean. I’d guess I’ve got something in the neighborhood of 50 hours on my K1 Pro, about 50/50 wood engraving and slate. I ALWAYS use some level of air and inspect the lens every 10 hours or so. I have not yet cleaned it once. Still looks brand new to me. Caveat Emptor. The frame, rods, and especially nozzle exterior and focusing “wart” have been cleaned several times, tho.