Zero.
The risk is to great when there are other options out there. If the book turns out to be good, then fine, what have a lost by waiting? A bonus, wh0 cares (my $80 bonis at PTS cost me $900). An opportunity for slightly unique lines, I'll catch them next time.
I may be an idiot, but I learning. Fool me once shame on you (ok shame on me for not heading the warnings), fool me twice, shame on me. Fool me 3x, call me old friend.
5 by 5