That is hilarious.
But also, ahem, to the point.
My test with pants is the sit test. Does the waistband dig in? Or, contrariwise, do I get a lot of pouffy fabric in the front?
I am more likely to buy my pants too big than too small, though. Wanting ease I sometimes end up with sloppy. It is a lesson Im trying to learn..
Shoes -- actually, it is hopeless. No trick I have ever tried has a guarantee attached. Despite my care over this, every couple of years I make an expensive mistake.
For dressier items, my tricks are: walk away and think for a few days. Do I need it?