Where to use Isolation devices

With your indulgence, a rant:
If I walk into a familiar room, full of knickknacks, I’m much more likely to notice a newly acquired knickknack, than I am to notice the removal of one. That’s because, over time, we all become consciously blind to details that are very familiar to us; or at least, we lose some awareness. Okay, where am I going with this? There is no element of audio that I find more agonizing than the struggle with isolation devices. Chief among woes, is that there is usually a give and take factor; and I notice what they add to the music long before I notice what was subtracted. Here’s the rub: since I can find no science to help me determine their proper usage - not to mention the outrages prices and snake-oil factor - I feel trapped. If I don’t use them, then what am I missing? And if I do use them, then what am I missing? Thank you for your indulgence.

The purchase and support of products that Claim to isolate should be a buyer beware alert. Isolation only exists in the absence of matter. Products that claim to isolate are a failure from the start based on such a premise that cannot deliver. At best these products merely re-tune your system to the flavor of the day. Mixing several of these non -isolation products together is the audible equivalent of trying to eat a soup sandwich. Resonant energy is still trapped and slow to leave it really needs to be provided a grounding pathway. Tom

Re-tuning or, better, correct tuning is perfectly fine with me. What is correct? Well, I trust my ears, the ears that actually listen.
One Kone and two corks? That's funny but why not if it sounds right? Somehow I doubt it though.

I found using Herbies Tenderfeet under Digital, and Isocups under all tube equipment has made me stop thinking about isolation, and that is worth the price of admission (whether they make a difference or not).

Another tangent that I've found unfortunately true is the placement of third party footers under any component. Initially trying the logical route of placing feet under power supplies, transport mechanisms, etc did not always end up being the optimal configuration. Also, I can hear slight differences that are usually a matter of give and take (ie in one configuration bass is more solid but sound is muddier, opposite for another configuration). Experimentation can be maddening. But I have, for the most part, consistently heard a difference with using after market footers. Many times not necessarily better.