That buried root flare from piled mulch is sneaky because the trunk looks totally normal from the front. I do the boot kick test around the base every single time now, takes 10 seconds and saves you from fighting a tree that's basically on a hidden hinge.

That stat matches what my mason told me last year when he repointed a section of my 1920s house. Water was getting behind the brick from a bad chimney flashing and the mortar on that whole side was soft and crumbling, but the brick itself was fine once we got it dried out. Pulled out about 20 bricks that were spalled and had to match them from a salvage yard, which was a pain. Now the first thing I do on any old wall is look at the top and the flashing, then poke the mortar with a screwdriver to see if it crumbles.