Poll:
1) Shards drop 3/day on average (2 from quests, 75% 1 from daily chance, 15% 2 from daily chance, 10% refill or WB from daily chance). New pack costs 15, old packs cost 10. Max 30 shards stored.
OR
2) Shards drop 2.25/day on average. All packs cost 10. Max 20 shards stored.
Note, clarified the drop rate on part 1 regarding the daily chance.