Just five years ago, it would have been insane to even think of an OEM or brand offering more than five- or (best case) seven-year warranty on a PSU. However, things change fast, especially when the competition is tough, and EVGA was the first to reach the ten-year warranty mark. Several years after EVGA's innovation, Seasonic has taken the lead, offering a 12-year warranty period to its PRIME series power supplies. Previously, they were covered by a ten-year warranty.
The upgraded warranty is retroactive, covering all PRIME units that have already been sold prior to this date.
In our opinion, any PSU warranty over five years is a serious gamble, because factors like the electric power quality and the weather conditions can have a significant affect on the longevity of a PSU, especially if it isn't protected by a surge arrester and/or a uninterruptible power supply (UPS). We're fairly certain that serious manufacturers, like Seasonic in this case, have already calculated the risks of providing such long warranties to products that are highly dependent on the protection levels that their users will offer.
Simply put, when there is a thunderstorm outside and you keep your PC in operation without a surge arrester or a UPS between the socket and the PSU, then you probably like to live on the edge. In addition, in areas with an unstable mains network, a PSU is highly stressed, and this of course leads to a shortened lifetime.
All of above make us skeptical when we see companies offering such long warranties, but then again, it's likely companies have evaluated an acceptable risk assessment around the issue.
In any case, Seasonic is well known for standing behind its products, and the decision to up the warranty on its PRIME platform clearly shows how confident its engineers are of its reliability. Now, in addition to offering top performance, the PRIMEs are also backed by the longest warranty available on the market today. It seems Seasonic wants to leave its most major competitor, Super Flower, behind in every area.