I don't generally hold seeds very long at all, as I start them indoors in October and November... they will not go into the gardens till June, so that can give them as long as 8 months growing indoors (which, here in zone 3, should knock at least one full year off waiting for them to bloom).
On the other hand... I have found viable daylily seeds in a (missed) dried seed pod (split open but still intact) outdoors in the garden after our long zone 3 cold winter!
Still on the scape, above ground, and in winter temps down to at least -30 (average winter)... yet the seeds had no special care, were not harvested quickly, were not dried or stored indoors... I put them into the ground in the garden that spring, and they grew.
Yet, I have 'lost' seed stored carefully indoors, dried for a week, then held (dry) in the crisper drawer.
If they are meant to grow, they will.
It's times like these when I seriously wonder how / why / when/ what the ??? There is just no logic ...
I also have gotten (many) seeds via the LA, and have had close to 100% germination this year (almost across the board, from multiple sellers). I only have (2) seed crosses that totally failed (both were gifts), so I don't plan to bother the sellers. And yes, a couple of crosses with low germination... But I've never had a better year for great germination, so if I lose one or two...