I just went through a set of Hannabach Exclusive MT that, although they have only been on the guitar for a little over a month, and show absolutely no wear on the basses, sound subdued and dull. This with less than 30 hours of play on them. In actuality it is more or less about 16 hours. They went dull just sitting there basically. They lost that special something that they had when I first put them on. I have had other strings which have kept their new sound, even though they sat in the case, on the guitar, for months without being played. But it ain't so with these strings.
I would definitely change your strings if they sat there for a year or two. Humidity and temperature changes won't do them any favors. I suggest that you tune it up and play a little on the old strings, just so you will be able to compare how good the new ones will sound after you put them on.