Say you torney edge is value X.

Should we take all-in spots that we know are <X ?

In cash games you can take every single +ev and 0ev spot and thats good, it adds up to give you edge.

In tournaments we can take spots that are +ev and again this also adds up to give you your edge.

But.... in tournaments we are always at risk of busting. Once we bust we can no longer gain. So how far should we push it? The small edges do add up to give us a bigger edge but they could be costly and may or may not be worth the varience. I do not know.

I'm talking about the stages before ICM becomes an issue.