Will frozen beef stay good for over a year?

Yes, beef can be frozen for a considerable time and still be edible. However, it must have been frozen quickly, thoroughly, and consistently. If you are in an area with frequent power failures, you might have to assume the beef was not frozen consistently. Partial thawing and refreezing will yield cell destruction and growth of very problematic bacteria. Excellent wrapping is also essential for long-term freezing. After a year, poorly wrapped beef will be dry and icky.