When I added a couple of splashes to some quick veggie fried rice, it gave the dish a depth of flavor I’ve never found with any grocery store brand soy sauce — which made it well worth its $20 ...
It is not always labelled as “aged soy sauce”; the brand I buy, Yuan’s, calls their version "royal soy sauce". It is expensive but is only used in small quantities. If you can’t find it ...
But the increasing use of airtight containers to bottle soy sauce by brands has begun breaking that habit in the last 10 years or so, as they allow the condiment to be kept at room temperature.