Barrel Life
The number of accurate rounds a barrel will fire before throat erosion degrades it past acceptable precision, which varies widely by cartridge.
Barrel life is the accurate round count a barrel delivers before throat erosion wears it past the point where it can still group well. It is measured in shots fired, not years, and the end usually arrives as steadily widening groups rather than a sudden failure, so shooters track it against a known baseline.
How quickly that count runs out depends heavily on the cartridge. Rounds with high overbore capacity burn large powder charges behind a small bore and generate sustained heat, which eats throats fast, while mild, efficient cartridges can last several times longer. Heat is the driver, so high chamber pressure, rapid strings, and hot loads all shorten the usable life of any given barrel.