Sep 18th 2012, 1:45:40
It really depends on your play style, which server, etc.
I've always favored keeping 10% of my land producing spies at all times. If I'm playing indy, 10% of production is always set to spies. Any other strat, 10% (or thereabouts) of my land is indy complexes producing 100% spies.
Probably overkill, but I'm a big fan of information.