What counts as "stronger"?

I'm going to use Hogs as an example in this because I think it's a clear-cut example. So when I'm looking at a Hog, what is it about the tree that makes the high say "this tree is stronger than that tree?"<br><br>I get that potency is one thing, but I can take a weak potency at high tolerance and not feel anything. Then I could smoke a high potency that I don't have tolerance for and be much more lifted. <br><br>I ask this because I'd like to know if the strongest Hogs would be beneficial for my depression? With that said, I'll also like to know how strong I should be looking for.<br><br>Edit: To elaborate, the term "stronger" is used so much and a lot of people use it in ways that make it seem like it's used to the point of being meaningless. I think you can go to any dispensary in the US and the bud tenders will tell you that every single strain they sell is not "mild" but "strong". I'm sure some of them have to be mild, but which ones and why?