In the beginning I saved them but than I need room for storage.
I did save Muffy letter when she moved out and the picture is still in the box.
Felt bad about letting her go but the bridge won.
Oh, god. I'm right on the brink of this with Static. I really want that bridge!
Ahem, back on topic. I don't really save letters, but I have saved a few. I kept the letter from the actual mayor and a few other cute letters from my villagers. But hardly any make the cut. I usually delete letters since they're just going to write basically the same thing in a few days anyway.