I still like how they get into corners, and for $9ish a brush, they are not bad. I am guessing all 6 or so of ours are from the same batch. Me personally, a Corona Cortex in semi-oval 2.5" sash configuration would be perfect for walls.
I am not sure on the exact age of that brush. At most, it has seen moderate to light use since late January. We have a few in rotation, so hard to pin point.
I personally spin brushes dry with my hands. I do not tap on my foot with the brush.
Once, fwiw, I kind did a quick flick of the brus (a Wooster) In the air, kind of a cracking the whip motion, and OT snapped the handle in two. I do not recommend that technique.