I've cycled through plenty of horses, and it's been more than just "test rides"
My first horse was a freebie / rescue, an ancient Arabian mare who was perfect (or would have been if she was ten years younger). She stayed sound until she started losing her teeth, eventually old age got her. Around the same time two more 'freebies' fell into our lap. Two more rescues, much less perfect than the first horse (not that any of that applies to the question).
I went horse-less for awhile and now I have Jackson BUT before him I tried out a handful of horses: 2 or 3 that I passed on immediately, another 2 oldies that didn't last long (one was retired to pasture, the other retired to a trail string), a greenie that was entirely the wrong horse for me and 1 that I free leased for about a year. It was the middle of my free lease when I went to see him and knew he was basically 'the one'. Horse shopping is a long process that can span a couple of years.