Microdosing, to me, means microdosing. Not low dosing.

If you want it to stay effective, and not build tolerance, and whatever other skewed bio-homeostasis effects, I suggest go down to single figure mg, or, even as the name suggests, into micrograms range. Try 100x-1000x less. Maybe try a break for months to reset to make microdosing effective again.

Can boost wellbeing/parasympathetic/braingrowth/healing effects with adaptogens (like ashvagandha) and other neurogens (like lion's mane mushroom/mycelia), and cannabinoids (like max dose CBD, 1200mg), and vitamins (whatever you're missing, fat soluble, B, C, etc) and magnesium (glycinate). This will keep it working good, better, for longer.

It depends really what you want out of it. Also, yes your tolerance increases pretty rapidly. I recently took a 250mg dose and didn't feel it. An hour later I took another, and ended up with some slight euphoria and visual effects. You can always take more, but you can never go back and take less!