AMT

I've never paid attention to alternative minimum tax. Under what circumstances would I choose AMT, if that's how it works.

Right now the AMT page looks like this (not the real numbers)

Alternative Minimum Taxable Income 250,000

Tentative Minimum Tax 30,000
Regular Tax 40,000

Alternative Minimum Tax 0.00

From what I've read, if the AMT is greater than the normally calc'd tax amount, I would be required to pay the AMT amount. Is that a correct understanding? If so it means it's irrelevant for this return.