With the cost of butter these days, I have to find it when it's on sale. I recently had some butter go rancid. Yes, it happens. Especially when it's unsalted. Seems the salt is the curative that keeps it fresh longer, even if it's not as good for you.
Now I get what I can afford, and if it's salted, I just don't use as much. I then put my oldest butter to the left and in one direction. Any cut sticks are on the left and in front.
The newest is on the right, going the opposite direction. This way, I am not opening new butter when I need to use the oldest first.
I hope this helps you.
Source: My slightly "over focused" brain!
I freeze unsalted butter all the time. No difference in taste or texture.
Freeze it! Butter freezes well and you just take out a new stick as needed. Will defrost in either the refrigerator or on the counter or if in a hurry and melted is ok use the microwave.
I keep my butter in the freezer. It will keep a long time. When I open a package, I still keep it in the refrigerator freezer but have it in a zip lock freezer bag instead of the package it comes in.