As a new owner of an A12t, I'm quite interested in this, as I wish to maintain them as best I can, however I suspect there is quite a large margin of YMMV with both topics.
Like you, I don't seem to generate a lot of earwax, but I do notice a very small amount on the A12t after several hours' use. I've cleaned them with a light alcohol solution applied to a microfibre cloth, and swept them with the brush, but so far there just hasn't been very much to clean. I typically clean all of my universals every week or two, but it's mostly just the tips that accumulate any wax residue, and it's really not very much. But that's me and my ears, other folks may have more wax then me. I'll see how I go with this set, but if I get another CIEM, I'll probably also get a vacuum. My view is that If I'm investing serious coin in multiple CIEMs, why not spend a small fraction more to keep them going for the long haul.
As far as the desiccant, yeah if you are sat at your desk listening with your CIEM, you're probably not sweating much if at all. However, if you are a stage performer, you may be sweating a lot, and in that case the desiccant would be very useful to maintain a valuable tool of the trade. Or, you might live somewhere humid, so again the desiccant would make a difference to you.
The question I have about the desiccant is: how frequently should it be replaced?
