[GMB]

OK, I think we have some confusion. I was commenting on capacitors in general and my remark about seriously small leakage was directed at non-electrolytic types.

As I went on to say, electrolytics are different in that they self repair (so long as things don't get out of hand).

The maximum voltage of a non-electrolytic is the point where catastrophic failure will occur so you don't want to go near that!

The maximum working voltage of an electrolytic capacitor is only what it says on the side when brand new. Once in service it will very gradually end up being whatever voltage the capacitor is subjected to because they do rely on the electrolytic process to maintain the dielectric but this can only be up to the actual voltage applied. So it's a moving target and thus unlike non-electrolytic types - something to be aware of if you recycle one to a circuit applying higher voltage (i.e. it will need reforming).

So electrolytic capacitors can fair better than expected without resistors - something that you could guess if you stop to consider how "non polarised" electrolytics are constructed. But they do need to be well matched, so things can still start to drift badly because although they self-repair it isn't as good as when they were made originally and depends on the exact conditions (they use a different electrolyte to form the dielectric during manufacture to get a more uniform thickness).