The word "rare" is not defined here. However, for most non-wildcard games, a
Straight Flush occurs every 7000 to 9400 hands on average, using max EV
strategy, depending on the game. Using that strategy at 9/6 JOB gives a SF
"cycle" of 9148 hands. At All American, which has the highest SF payoff of any
standard game I know of, the "cycle" is 7053 hands. At 8/5 BP, it's 9360 hands.
If you set all other (non SF) payoffs to zero on WinPoker, and therefore
reduce the SF "cycle" to its lowest possible number, you get "occurs every" 3180
hands. Personally, I do consider this to be "rare." With "normal" max EV
strategy, SFs occur about five times as often as a Royal, which I would classify
as "very rare."
Should a casino offer a HUGE bonus (or a high progressive) for a SF, then
you might, with the correct max EV strategy changes, get a "cycle" of under
7000 hands. But not by much. Still rare.
If, however, you define "rare" as the chances of being hit by lightning in
your living room within the next five minutes, then SFs are pretty common. 
JMO.
Brian
ยทยทยท
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In a message dated 7/24/2006 8:38:13 PM Pacific Standard Time,
jacobs@xmission.com writes:
For example, it seems that
straight flushes should pay much more than 250 for how rare they are.
They are rare because the playing strategy makes them rare.
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