When does it pay to play deep?

Originally Posted by Fnord

At least one of 4 things must be true:

• Your opponent will call off his entire effective stack with too wide of a range of hands.
  You opponent will bluff off his entire effective stack too often.
  You can read your opponent's hand well enough to get in an extra value bet or value bluff if you played an additional bet/street.
  Your opponent will fold medium strength hands to implied threat on what otherwise would be an all-in street.

Against solid regulars #4 is often the only reason to play deep. But it can be a compelling one.

Originally Posted by Fnord

I'll argue that if none of these are true, you're better off with less than 100x the Big Blind. Although I'm not sure about the last one. Any others I might have missed?

Those seem to sum it up. Another might be if your opponent doesn't widen his range pre-flop to take advantage of implied odds, but that also depends on #1 or #3 being true to be profitable. I'd also add that if you don't have position on the other deep stack(s) that's a good reason to leave the table.