Not the first time this has been asked. Any search in this group will find that it has been discussed before.
The manual specified 30 days as a recommended changing point.
I asked the question why as well.
The answer I was able to dig up was because of the light aspect of DNA, which has a 30 day observable phenomenon. The author took this into consideration when drafting up guidelines for all DNA samples discussed in the manual.
Well the question is, does that matter?
So like anyone who really wants to know should do, I tested it out rather than just theorize.
I still have DNA in use dated 2015. You know what, I personally found out that I still retained efficacy with my old samples.
Why do I not push this out as an agenda to be changed?
Because of free will. You can elect to change it out if you wish, or not.
Some feel that changing it out makes a difference. Well even I have registered some level of decreased efficacy with older nail samples, but not enough to warrant a mandatory 30 day change.
Any search on viability of DNA for forensic analysis will show that 30 days is not an expiration date.
A little research, common sense, and actual testing goes a long way to answering questions.
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