Professional No-Limit Hold 'Em Questions

[D. Andrew]

I was hoping some of you could help me with a few questions I have about topics in the book.

1. Don't put in 1/3 or more of your starting stack and then fold. Why is 1/3 so key? I understand that after 1/3 is in the pot another pot sized bet (in heads up situation) will be for all the remaining chips, but why should I not fold to that remaining bet? On a related subject, why have I most likely made a mistake somewhere in the hand if I do put in 1/3 and then fold?

2. You want to play hands around the possibility of getting all-in. This is the most general principle for which commitment and SPRs is based. Do we really get all-in enough times for this to be the main focus? Is the majority of our expectation derived from these situations? Should I not play hands around the possibility that I might not want to get all-in?

3. Commitment is good. Why is this true? Why is being committed better than not being committed? Why am I planning my hands around the goal of commitment?

As a side note, When my AK misses I would much rather have an SPR of 13 than 4.