I do 0.2mm prints all the time, and 0.4mm (infill every 2 layers) always ends up a bit manky for me (0.35mm nozzle on the E3D - best not to exceed nozzle diameter with layer height in any form), so I stick to infill every layer.

You really should experiment with infill density all the way from zero to 100%.
You only need to fill every so many layers if the design needs it.  I rarely use that feature but I change infill routinely.  Most of my stuff is utilitarian in nature so I print a lot at 100%
Have fun with it as you may just change how you design  stuff as well.

+1...

But if your prints are more aesthetic or very large, then try 20-50% infill.  Also, for 0.3mm layer height, set the infill to fill every 1 layer.  If you are printing at 0.1mm layer height, then set infill to fill every 3 layers as this will save you a lot of print time. There is no reason to print infill at 0.1mm layer heights!

Other than that...Experiment with it and have fun!