One of the reasons I frustrate myself getting a good new production S&W revolver with frame-mounted firing pin to carry: no hammer nose to break.
Through tens of thousands of rounds through dozens of original style hammer S&W revolvers, I've only broken THREE hammer noses - all on the same gun!
I was issued a S&W 13-3 3" HB at the FBI Academy in 1986. It didn't appear to be a brand new gun, as it had a bit of muzzle and cylinder wear. I had been shooting revolvers regularly for the past 4 years (mostly a Ruger Security-Six), so could tell the difference.
In the sixth week of training - about 1500 rounds of .38 Special wadcutter into it - the hammer nose broke while we practiced prone firing at 50 yards. The PFI asked me how I broke the gun; of course he knew better, but he has to be a jerk to trainees. I went to the Gun Vault and they issued me a replacement for the rest of the shooting session.
My original issue was repaired before qualification day and everything went fine. We continued shooting, switching to combat and movement type courses. In the twelfth week during during a combat course, the hammer nose broke again. Revolver had about 2500 rounds fired by me at that point, mostly wadcutter but about 150 rounds of +P service ammo. Back to the Gun Vault for a loaner. By graduation in the thirteenth week, the original was returned repaired.
In the field we trained and qualified quarterly. During my third quarterly session, the hammer nose broke off again. Total round count to that point was about 3500 rounds. I was thoroughly disgusted with the weapon, and had no confidence in it. I also was rather piqued that no one at the Gun Vault would wonder why this particular revolver kept breaking hammer noses, and replace the entire gun, rather than keep fixing a broken clock. Poor record keeping I suppose.
At that time, if you had your own approved personal weapons, you could turn in your issue gun. I did that, and carried my own guns for the remaining 33 years of my career.
Never broke a hammer nose since.
Anything mechanical can break at an inopportune moment. I keep my defense guns well-maintained, regularly check for wear, and don't see the point of shooting nuclear-level loads through them.
I always carried a BUG during my career. Rarely in retirement. But as I soon approach the day when running or hand-to-hand fighting doesn't work like it used to, one of these as a spare has it's merits: