This thread needs a bump but I decided to throw out a nifty-looking chart this time.
We all know that we always have equity when someone calls our raise, so we know that a blind steal that is exactly break even just from fold equity will be +EV since we will [hopefully] be +EV post-flop with our positional advantages the times we are just called. To give an idea of how much this can change things, I threw together a quick chart to show some numbers for a hypothetical situation in which both blinds fold or we are only called by 1 blind. On this chart, x is the minimal amount of post-flop equity we are assuming we have, y=f(x) is the amount of times both blinds would have to fold for us to break even based on the appropriate x, and the last column is the square root of y, which is how often each blind would have to fold for us to break even if they always fold the same % of hands.
Code:
x y=f(x) sqr(y)
--------------------
0.00 0.7273 0.8528
0.01 0.7245 0.8512
0.02 0.7217 0.8495
0.03 0.7188 0.8478
0.04 0.7159 0.8461
0.05 0.7129 0.8443
0.06 0.7099 0.8425
0.07 0.7067 0.8407
0.08 0.7036 0.8388
0.09 0.7003 0.8368
0.10 0.6970 0.8348
0.11 0.6936 0.8328
0.12 0.6901 0.8307
0.13 0.6865 0.8286
0.14 0.6829 0.8264
0.15 0.6791 0.8241
0.16 0.6753 0.8218
0.17 0.6714 0.8194
0.18 0.6674 0.8169
0.19 0.6633 0.8144
0.20 0.6591 0.8118
0.21 0.6548 0.8092
0.22 0.6503 0.8064
0.23 0.6458 0.8036
0.24 0.6411 0.8007
0.25 0.6364 0.7977
0.26 0.6314 0.7946
0.27 0.6264 0.7915
0.28 0.6212 0.7882
0.29 0.6159 0.7848