There's basically 3 factors that'll ruin or shorten a barrel's life. You've ruled out the 1st 1 of excessive heat, so that leaves crown damage from improper cleaning (ALWAYS better to clean from breech end and using jag instead of slotted tip), and lack of proper cleaning. Breaking the barrel in properly will result in easier to clean barrel, same as hand lapping bore. With proper care, you're barrel will still be around and shooting good longer than you will-unless you're planning on shooting untold thousands of shots, and even then it'll likely outlast you. If you have the money to shoot THAT MUCH, you'll have the money to rebarrel it several thousand shots later.