I freeze butter all the time. I don't exactly know how long I've left it in the freezer before using it, but I've never had it come out badly. The recommended limit is 6-9 months (National Center for Home Food Preservation).
Thanks Bluecat and Barb L - just missed a bargain at the local supermarket. French butter with sea salt chrystals going for 25p (that's cheap here in England). Never mind though, at least I'll know for next time.
Location: I live in the Heartland of the United States - Western Kentucky
I freeze butter regularly and usually keep several pounds in the freezer. Most of the time, I use it within a month or two. Never noticed any adverse effects from freezing it. The plus for me is convenience. We live nearly 30 miles from our nearest comprehensive market.
"As a girl I had zero interest in the stove." - Julia Child
This is real inspiration. Look what Julia became!