How does one "waste" a limit break?

[Pells]

Eh, this stuff happens. Using the LB is always a judgment call and while it's easy for anyone to type "lb" it is not so easy for a dps to type:
"After careful analysis of the situation, I believe that the LB would best be used for this purpose and at this time. Of course, I would hate to unilaterally decide this for the entire party, so I shall await unanimous agreement on this matter before pulling the trigger."
...That would be absurd.

You could macro it. And tack the limit break onto the end of it. Y'know, since you've asked so nice and all.