How Much Capital Should You Put Into a Stock?

What is the highest level of concentration an individual investor should be willing to place into a single stock when buying? Specifically asking about non special situations, more long term holdings. Presumably at some point cat risk is too high, even when you have an edge. It's hard to say. If you're earning money every year and saving, then obviously you can afford to put a hundred % in am because actually catrusk doesn't present much of a problem to you not being able to invest over the long term. However, if youare taking all the savings that you'd made, and now you're retiring and you know you'll never make any money again, then it's severely dangerous.