why wouldn’t the files “keep”?

I am rewatching the show from the beginning, and in S1E2, Dylan says that they only get 1 out of 5 files done per quarter, on average, before they are no good any more. He says that they “don’t keep” or expire.

Based on what we now are caught up to date with in relation to each of the files and the correlating rooms that Gemma goes into, why would the files not keep? I don’t think it would have to do with anything actually relating to a quarterly basis, as Gemma has been on the testing floor for much longer than the duration of a quarter at this point in the show. It’s not like these files were all completed within the same quarter.

I just need to know what they are doing that would mean that the data, if not sorted in a timely manner, is no longer eligible to used in the creation of the rooms!