Wrapping my head around greening up and EV calculations?

[favetelinguis]

I find one of the hardes thing to get my head around is the ins and outs of greening up. For example, how would you answer the following questions?

1. Why would you not always green up after every bet?
When watching trading movies people are going about there trading and then ONLY ONCE before the race start they green up, would it not be better to just green up on each bet?

2. Why is it always better to green up when trading?
It seems like greening up is the default choice for traders but is it really that easy? It must depend on the expected value (ev) of the other choices are?
For example you have to calculate the ev of leaving the bet och just making a offset bet. Is the ev always higher for greening up?

[ShaunWhite]

I find one of the hardes thing to get my head around is the ins and outs of greening up. For example, how would you answer the following questions?

1. Why would you not always green up after every bet?
When watching trading movies people are going about there trading and then ONLY ONCE before the race start they green up, would it not be better to just green up on each bet?

2. Why is it always better to green up when trading?
It seems like greening up is the default choice for traders but is it really that easy? It must depend on the expected value (ev) of the other choices are?
For example you have to calculate the ev of leaving the bet och just making a offset bet. Is the ev always higher for greening up?

1. I can see why people do both, I don't think either is wrong. The only thing I try and do is to green at the lowest odds possible, sometimes that's at the end, sometimes it's before a reversal.


2. It's basically to smooth out your income. Calculating an ev would be impossible for me as I don't know one end of a horse from another. There's simply too many races to do the maths for what might, and only might, be a very small gain.