So far the only issue I've had with mine was having to replace the recoil buffer. I think it was around $15 from Numrich (p/n 765630).
This is a mysterious part you show here, I went to the Numrich site and what it shows appears to be a rubbery-plastic part similar to the Wilson Shok-Buff item of 1911 fame -- or to be more direct, the
infamous Shok-Buff that most swear against and even Wilson doesn't install in their pistols.
I have found limited use for these in some places, but this is definitely -NOT- a stock, original part for any Smith & Wesson 1-2-3rd Gen pistol. You shouldn't have one in there that needs to be replaced, it's outside the design of the gun.
It seems quite often we have threads here by folks who want to stock up on arguably "consumable" parts of seemingly indestructible guns simply because they are out of production. The easiest (and typically best, most accurate) answer is... buy some springs from Wolff, buy extra magazines when you see them and if you honestly believe other parts are going to fail -- buy a second, back-up handgun in the same model. If we are talking a 5906 or 4006 or 915, this is not only EASY, but it's cheap too. It's the best answer. On a 1006, not so simple or low in cost.
But it's no less the God's honest truth. If you keep good springs in it and you keep the pistol lubed and you use proper, in-spec ammo and you care for the pistol like it you ought to, the raw numbers bear it out... simple cost of the ammo it would take to "wear out" a 1006 is more (far more) than it'd cost to buy another 1006.
In my opinion, and without trying to offend, but this "oh my, out of production, I need spare parts!" is really a whole lot of nervous, unnecessary energy.
Additionally-- yes, these are out of production and yes, S&W cannot be counted to on fix, repair or be the magic answer if something fails. However, contrary to what is (far too often) said, S&W
DOES still have some parts! And Numrich is a constant cycle of parts in and out, what they may not have today may come in next week, as this is precisely their business. Their parts come from guns taken out of service. On top of that, Gunbroker and other venues show parts here and there and the folks on exactly this forum can sometimes come up with specific parts
WHEN they are needed, so that is my recommendation for going forward in to the future with your 1006.