Thanks for detailed reply...



That's what I meant by "small". I know there are big ceramic capacitors (I myself have one around in my cellar, it's a 10x10x5cm box) (and some of them are pretty much unreplacable in applications where you encounter reversal of polarity, but with their size they seem to be a necessary evil), but if I want i.e. the 33pF capacitors driving the crystal, 100nF decoupling, a minimal transfer delay, a low-pass filter against very high frequencies or anything, where I never use anything more than 500nF, is there a reason to use electrolytic instead of i.e. NP0 or X7R? I mean, in some situations electrolytic capacitors may be even very undesirable, i.e. decoupling a "dirty" line - you assume the fixed polarity between +5V and GND, but then suddenly a bad negative spike comes, +5V momentarily shifts to -3V, your other hardware will survive this, the capacitor may die or have its life expectancy reduced...?