It's been months and months without finding a silver quarter... at least $10,000 in quarters searched... wish me luck! I just picked up $470 in quarters from the last bank I did get a silver quarter from all those months ago (May or June)...
It's pretty spontaneous. I've only found two in the past 2 years- a beat up 1948, and a nicer 1956 or 1957, I think. Be sure to look out for Ws and 4th of July privys- I've found much more Ws out there, both in change and in rolls. All the silver has been plucked out in the 1960s and early 1970s. I've been on a dry streak with halves meanwhile- did find a couple of 1987s, whole bunch of NIFCs, but only one 1964 in $1200 worth of coin. Side note- crazy to think that Ws are worth as much, sometimes more than a silver quarter.