It depends. . .
Caliber/pressure (BIG effects), chrome or non-chrome bore, types of bullets and even powder type (smaller effects) can all change the number of rounds.
Assuming .308, regular steel, no chrome lining, and standard gilding metal jackets on your bullets, PLUS no abuse of the crown or abuse of the throat (corrosion from mixing cleaners, etc.)---->accuracy generally improves for 2-3,000 rounds, stays steady or even gets a bit better until at least 7,000 rounds. The dropoff in accuracy tends to be gradual and may not even begin until more than 10,000 rounds. You're lucky if group sizes are less than 50% bigger than the peak accuracy at 15,000 rounds.
Whether that's still enough accuracy for your purposes is up to you. Barrel throats can be almost gone, while the total system still performs less than 2 MOA, sometimes even at 1.25 MOA or less.