The S&W Model 10 is a fine double action revolver. The Model 10 is a K Frame. police trade-ins can be excellent buys. Most police sidearms are carried a lot and shot a little. The 3 and 4" barrels make great self defense guns and are nice for informal range practice. You didn't mention a price, but if you can get one for $250 or less, I'd consider it a good buy. BTW, the Model 10 is a very durable design and you aren't likely to wear one out in your life time...even a used one. Often, for a few dollars more, you can get a "select" grade gun. It is probably worth the extra money to do so. Another thing to consider is the fact that most anything that needs repaired on a Model 10 can be done at a reasonable cost. Parts are widely available. I'm a retired police officer and served as a firearms instructor for many years, so I know a few things about S&W revolvers.