I know from info here DPD powder lasts a year. That would seem to be because it is opened often and exposed to the atmosphere (absorbs moisture I think).

I was thinking about buying 1/4 Lb and every year open it up to fill the 10 gram vial with enough for the year (or close to it) recapping the bulk container.

1/4 lb is 113 grams, so roughly I would be storing 10X what you get in the 10 gram vial for a little over 3X the cost (I roughly calc'd in shipping). If it lasted 3-4 years I would be even.

The price looks good on paper, but wonder if the bulk could last the several (10???) years it would take to use it up?