To get that part out of the way, our complete statistics show about 1,300 employee names that are currently "inactive", meaning they've separated from our employment for some reason. About 100 quit, for various reasons ranging from not liking the job, getting a better offer elsewhere, moving, etc. Around 100 were separated for reasons that were neither a firing nor a quitting - such as lost their eligibility to hold the job (lost drivers license for a moving violation, jailed, refused to take drug test, etc.); died/injured outside of work, job was eliminated, etc. But over 1,000, closer to 1,100, were fired.

The top 5 reasons I fired them were:
Stealing (a staggering 60% or more)

Insubordination
Negligence/accident
Work ethic (tardiness, excessive abscences)
Incompetence (less than 5%)
What that says to me is that your ability to do your job is the least of your worries, and your ability to hold onto your job most likely has little to do with your ability to do your job. Of course, working in the automotive field as 6 of our 9 businesses were, is somewhat self-filtering. People would at least have an inkling of what it would take to work in an auto shop before they'd even apply, so the ability to do the job is probably already there. If they don't already have the qualifications, they may at least have the desire, and a position may be open that can be trained for, so it will be known in short order if the person can actually perform the physical requirements of the job itself.