Haven’t had to clean the lens yet - after two and a half months of normal usage. I do wipe the windows over the lens every other week or so, and the camera in the lid. (ALWAYS with the unit turned off.)
I ran out of lens wipes after the first cleaning. I use a special non-scratching lens cleaning cloth spritzed lightly with a 50/50 vinegar/water cleaning solution to remove the smut. What you are dealing with is a thin film similar to what you find on the bottom of an ash tray. The same slightly oily film can be found on glass shelves if you happen to have them…it just smears if you don’t cut the oil with something. A quick gentle wipe with the vinegar solution removes it.
I also clean the grime/soot/ ashes off of the tube when needed…again, always with the unit turned off.
Some operations (like deep engraving) create a much messier environment in the closed case than others, and some materials are worse than others. (Some plywoods are bad depending on the glues, acrylic is worse, extruded acrylic is horrible from a smell standpoint, eggshells are the worst for throwing up powder fine particles…you will have to dust the tube between eggshells and anything else. Haven’t tried stone but it might be the same for those…working with minerals in both cases…it seems to pulverize the material instead of actually burning it. Don’t know yet…still have a lot of learning to do.)
Point is…there are probably going to be different cleaning requirements for different usage, and that’s going to vary based on the user, and what they are trying to do with it. Until you actually start using the machine, you won’t really know what your cleaning schedule is going to look like.
But in any case, it’s not particularly difficult or often.