In general or specifically with Paizo?
Usually I allow about 1-2 weeks for a reply, depending on the nature of my communications, the size of the organization involved, and my needs. Major complaints to large companies regarding damaging or life-threatening matters I expect pretty much instant acknowledgement, if not immediate decisions; a group like Paizo I'd be much more lenient with.
After about 2 weeks, however, I'd do some follow-through, possibly even a telephone call.