My experience was having brand new rubbers going within weeks (seller A, product X) - these would have allowed dirt ingress very quickly which would quite easily cause the joint to fail within the first year.
The solution for me was to fit aftermarket replacement rubber boots provided by the supplier at no cost, and in my opinion far better suited to compression within the limited space between wishbone and knuckle - there is NO WAY the particular rubbers that came with the my replacement ball joints were supposed to compress the way they did.
So either I have an oversized taper in the knuckle or something, or the shape of boot on the supplied ball joint was incorrect for the application.
It makes me wonder whether, for many of the <1year ball joint failures, "it's all in the boot"...??
Picture below - rubber after two weeks and a couple of hundred miles...
Just for the sake of illustration (no relationship to the sellers, parts, quality, etc...)
- style of boot that works for me...
here
- style of boot that did not work for me...
here
Further caveat - I've picked those two links on appearance/profile alone. I accept there may be differences despite appearances, that not all parts are equal, etc... Folk do use many sellers for replacement ball joints on existing wishbones and they can last for years.
It does make we wonder, though. If an incorrect boot is overstressed from day one, the symptom could well be a short life, as many people do experience. It may not be simply down to an inherently lesser quality part, just the boot on top of it. That said, I thoroughly approve the use of metal bandsaws for comparative testing!
(Sorry to hijack the thread - good luck with yours!)
And passenger side had split boot with holes, but no play. 
