All good responses above - I second them.

I have been buying a lot of them.  Once you are actively doing it, you will find like the poster above said that you will stumble upon some really good cattle while you are planning to buy junk.  Do not get discouraged by death loss.  They are old, some will croak.  Sometimes they drop a crappy calf and you just found out why she was culled.  You need to know your break even very well so that you can accurately price in death loss when you are at the sale barn purchasing more old gals.

Do not think you can buy a cow with a bad foot or a bad udder and straighten her out.  They probably already tried.

We never rebreed a truly old broken mouth - you should just be happy you got the last calf out of her, and move on to another one.  If she is a short solid with solid feet and four good quarters, she gets another chance, but err on the side of culling.

The difference between success and failure for me is the cost of the feed.  You can not pay market value for a normal cow ration - at least I cannot around here.  Byproducts and cheap forage are your friends.

Good old skinny cows that just have not gotten the groceries can be fattened up so you make money on the calf and also when you sell the cow by the pound.  Bad old skinny cows will just break even or cost you money - less money when selling the calf, less money when selling cow by the pound.

Buy them for killer price, because most will get sold for killer price.

I do enjoy it.