Starter Issues

What could be causing the starter to keep going
bad? I’ve had to replace the starter 4 times since
May of last year. The one on there now has gone
bad & it’s only been on there since the end of
November 2017. On bench test it doesn’t kick out &
spin every time like it’s supposed to. This has been
the case with every starter that’s been put on there:
they’ll either spin but won’t kick out or they’ll kick
out but won’t spin. I’m out of ideas as to what’s
causing this, & I’m also running out of patience,
time & energy. Thankfully there’s a limited lifetime
warranty on the starter so a replacement isn’t
costing me anything other than time, energy &
patience. My car has almost 200,000 miles on it.