I'm currently shooting a Beretta AL390 in sportingclays competition, and it approaching 150,000 rounds. Its running fine. I've replaced maybe $50 worht of small parts, usually in preventive maintinance. On the subject of reciever or major componet wear, the originals[reciever, barrel, etc.] are holding up fine. I have gotten a couple of hair line cracks in the buttstock, but the stock was heavily modified, so its tough to blame that on Beretta. Suits me fine, I spring for a new buttstock, or I may just rap this one with tape
IMHO, there is no finer gas operated auto shotgun made, and we will see if the new Beretta 391 can live up to its ancestors.
In general terms, most modern 12 ga repeaters should last longer than the shooters. I've got the Rem. 870 that I started hunting with when I was 13[22 years ago]. Its still working fine. I've broken 1 firing pin in all that time. You will get tired before the gun does.
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Stay Sharp!
Will Fennell/CAMILLUS CUTLERY