Thanks. I guess I better prepare for a bigger archiving project then.
Perhaps it depends on how you define "archival". If you want every negative to last for 100+ years, you need to consider the negatives themselves and their processing. B&W can be tested for residual hypo products, etc., but the life of color negs is more debatable, even when properly processed. And you then have the concern of choosing truly archival storage products and their cost.
If you're more pragmatic, do you
really need your negs to last that long ? I'm sure that a lot of my own negs and prints will finish in the trash when the time comes, but I'm realistic to believe it's that the pleasure which I have had in making them which really matters, not any great artistic or historical merit. So my storage is largely in the supplied sleeves, or similar cheaper general purpose sleeves if home processed.
OTOH, for the few sets which I hope might be of future value (historic places now demolised, steam locomotives long scrapped, that sort of subject), I have spent the necessary $ to buy quality storage (which I certainly couldn't afford if I tried to archivally save every shot I've ever taken, good or bad).