When did CGC cases change (re: re-holdering every 7 yrs?) 0

[CKinTO]

All - apologies if there is a thread on this already, but couldn't find it with a search. I know at some point with the older v2 CGC cases (the ones right before the change in mid-2016 to the current newer-style cases, but without the inner-well), CGC changed its recommendation around getting slabs re-holdered every 7 years. I think the original rationale for the 7yr reco was that the micro-chamber paper may get "used up", or maybe something to do with the plastic used for the inner casing, I don't recall exactly.

Anyways, I've recently bought a "v2 slab" (graded in 2005), and wanted to see if this was pre-reco change, and whether it would be wise to get re-holdered. Let's put value of the book aside for now, purely from a "maximizing longevity" perspective (it's only worth about $100, but it's got sentimental value, so the cost to ship/re-holder to me would be worth it assuming it's advisable). Thanks