Well it all depends on the Products life and how long it will be used and how long you are legally responsible for its safety. You never gave specifics to what industry you are in.
Without knowing specifics, I would say keep the data forever. Two reasons, space is super cheap now. You can get hundreds of terabytes of space for almost nothing, you can burn the data to discs, platters, etc. The second reason, legally when data is not available and it is proven you got rid of it or deleted it, it is the same as saying we are guilty that is why we got rid of it.
So just to be safe, keep it and keep all of it, remember you can archive files, hard drives, platters, etc a whole lot cheaper than you can defend a lawsuit, especially when the evidence that would have proven your innocence has been deleted.