Guns are individuals, just like people. Loads are also pretty variable. How people care for their guns influences how long they last. Above, its already been stated that shooting he hell out of an already hot barrel isn't good.
We go back to the old discussion on how long your gun will last. Do you clean it? If you shoot cast bullets, do you clean the bore regularly and look for leading? If leading starts to appear, so you even know what it looks like. Or what the tight patch looks like?
When people ask how many rounds a M10 will last, I'm always amused. These are often the guys who buy a gun and start to worry after the 2nd or 3rd box of 158s go down range. Relax. Most K frame guns with modest or target loads will go maybe 100,000 rounds. I like to use .38s as examples because the ammo is so cheap. These days, you can get 100 rounds at Wally World for maybe $20 or so. The first 1000 will cost you $200, the first 10,000 will run $2,000. And by the time its rattly, you'll have paid $20,000 in ammo, and nearly as much in range fees and fuel, lunch and supplies. Not bad service from a second glance level gun.
N frame guns don't last that long. Maybe not half as long. But the ammo costs nearly twice as much. If in total, you've blown $600 on a gun and $20,000 on ammo, and it starts to get loose as a goose, sell it. Get your $600 back. It probably only cost you $300 20 years earlier, anyway.
Nice old N frames, or even nice new ones have a lot of life in them. If you want to see how much powder you can put in a case, buy a not so nice gun. Its the other brand, built like a brick, finished like one, too. Inside and out.
Use factory ammo, or handloaded equivalents. Most of us do as related above, we shoot target level loads because they're a lot more fun to fire. My old hands hurt when I fire my 329 with 240 grain full power loads. I don't care how many of them will work. More than I plan on shooting.
Keep cost in mind when you make these comparisons. If you fear wearing one out, sell it after the first 1,000 rounds and start over. Sell it cheap... to me...