There was a VERY secret study done by a major firearms company about a decade ago that concluded most handguns were fired less than 100 rounds in their entire working life.
RE: Sigs folded versus milled...no difference one way or the other. I own both. The 210 suffers from the same problem as all the older guns, be they Thompson submachineguns or Colt Python revolvers...it was designed to be hand-fitted and basically supplied in what we would now consider small numbers. In fact, modern manufacturing techniques are better than much of the previous hand-fit guns...for every 210 or Python, there were a thousand other handguns that just didn't deliver the accuracy and reliability because of inconsistancy in parts and fitting. remember the 1911s of 20 years ago? We thoguht of them as the ultimate "kit gun," in that a gunsmith had to overhaul the thing before it would run. Now, the most accurate and reliable out-of-the-box 1911s in the world come with barrels that are fitted by computer-controlled machinery...notice I don't mention which one, because too many people would have a stroke.
BTW, take an out-of-the-box 210 and shoot it against an out-of-the-box 226 X-5...betcha the X-5 is every bit the long-distance gun the 210 was. Better ergonomically by a substantial margin. Cost about the same in equivalent dollars...
Michael B