Stat Weights: When is it enough?

[Sharlikran 0]

What I never understood is just because the stat weight says that Mastery and Crit is more important, how do you decide when to sacrifice some Mastery and Crit to keep or have some Haste?  Should I have 15%-20% Haste and then dump the rest into Mastery and Crit?  Is there a theoretical cap for Haste that you shouldn't go over because you would sacrifice too much Mastery and Crit, and therefore DPS?

Crit 25% (967)

Haste 16% (1649)

Mastery 47% (1408)

[Azortharion 60]

You will never reach a point where you make that decision. If there was a cap for Haste that was worth reaching, the guide would obviously say this.