How long can you keep beef frozen?

Answer 1

Until it molds

Which would be a very long time. Mold doesn't grow in a properly cold freezer (usually 0-10F.)

Really you can keep food frozen until it dries out, and even longer if you're ok with freezer burned food or it is something you can rehydrate effectively.

Beef tends to toughen the longer you keep it in the freezer, so have that in mind with what you want to use it for.

Hamburgers, for example, are best with the freshest beef you can use, while taco meat, or other dishes where you break up the meat while cooking, is not as bad with old frozen meat.

Answer 2

Beef can be frozen for 1 year, and even longer if stored in a deep freeze (0 degrees or lower) A deep freeze is a freezer with no automatic defroster.

Most if not all home freezer compartments on kitchen refrigerators have a defrost cycle which causes the inside of the freezer to warm slightly to keep ice from building up.

Good for your freezer, bad for frozen food that also gets warmed slightly each time the defroster cycles. It is this slight thaw then subsequent refreezing which causes "freezer burn".