I don't think that's as long as we could possibly care, but it's a good concrete number. The Stelliferous Era is predicted to last some 10¹³ years; looking at their Arrhenius plot, we probably need to keep the temperature below about 400 K to last that long. (However, I suspect that over such long time scales, other decay mechanisms such as cosmic-ray damage will be more important.)
Most likely, for long-term archival, we need to make copies of the data from time to time. But this technique will likely allow those intervals to be longer than the current age of the universe, and it offers higher density than you can get with techniques like Norsam's planar discs, which is a useful improvement over existing media.
Most likely, for long-term archival, we need to make copies of the data from time to time. But this technique will likely allow those intervals to be longer than the current age of the universe, and it offers higher density than you can get with techniques like Norsam's planar discs, which is a useful improvement over existing media.