If it's a rune, it gets picked up. Once I get seven of a kind, three of them get cubed up - that leaves four on hand for runewords, crafting, repairs, upgrading if desperate, and so on.
This tactic hasn't gotten me a Zod yet, sadly, but one day (in about 60 years time) it will. You'll see. *laughs maniacally*
(edit: as an aside, I tend not to upgrade gems unless I have them handy or want to use them. This way I always have chipped gems on hand for cube recipes too.)