As a general rule I have never submitted a search warrant on a drug case unless the "fresh" probable cause was within 72 hours of the issuance of the search warrant. This was the rule I was taught. An officer questioned me about this and I have researched this issue. I can't find where this is a rule. Does the fresh P.C. for a search warrant on a residence in relation to illicit drugs have to be within 72 hours of the issuance of the warrant? I was always taught you needed "fresh" P.C. When does P.C. become "stale" or does it?

Freshness of PC is going to be determined on a case-by-case business. The 72-hour rule is a good one if all you have is a single sighting of drugs, but if you have something that indicates a continuing or ongoing possession, then your PC will stay fresh longer. So if you did trash searches once a week for a month and found drug paraphernalia every time, then last week's search would probably still provide PC for a warrant.