There is a proper technique and if not followed, the joints can fail. ?The install you mention might just be lousy installation. ?I don't recall the specs, but I would not be surprised if there's an allowed installation temperature range too, since PEX is thermoplastic.
Of course this is a bit newfangled, and the 50-year performance of these fittings surely isn't known. ?On the other hand, people often think copper lasts forever, but that's not true either. ? In fact, copper can fail surprisingly fast (a few years) when not done right.
The ultimate in crimped PEX fittings is Viega PEX press. ?If anything lasts forever, that will, but the fittings are not cheap and the install tools are quite expensive. ?I've never seen a DIYer using it.
Mark
