'On the Go' water softening device- orange granules

resin cannot be dry - ever. So you'll need to be careful storing it if you don't use it all up.

The only thing you'll lose when you lost resin is capacity - water will go hard quicker.

Call around at water purification services for resin prices. It varies a lot. For my home softener I was able to buy Dow brand resin for $70 for a cu ft. There are cheaper brands but I do have to say switching to the Dow brand I'm going longer between recharges - even compared to when my softener was new.