Anyways, my test for a vacuum-sealed tin is to feel whether the flat surfaces still feel sucked-in or not. Try pinching it hard like in your picture of the Royal Yacht tin and see how easily it gives. If it feels pretty solid, the seal is probably still good. If it feels squishy, I'd open it up and inspect the contents.
This test is not perfect, of course, but it gives me actionable steps so that I don't have to worry as much about what's in my cellar.
So I got home from work and I tired that on a tin that I was pretty sure I had opened and it felt squishy, but when I cracked it open it hissed like it had been re-sealed and the tobacco was still moist! I'll transfer it to a jar when I can get another one but I think because the room that its in isn't temperature controlled maybe it re-sealed itself as the temp fluctuated. The rest seemed to hold up to the hand pressure besides a very rusty Sam Gawith tin and some aromatic that I dont remember caring for. I think I'm a lucky man, hopefully this tides the TAD but I think we all know that's not gonna happen.
