check is in the mail

carry the mail

To work diligently; to serve as the principal performer of a demanding task or set of tasks.

check and balance

Provide mutual oversight and limitation by independent organizations in order to prevent abuses of power.

check the math

To verify the source or accuracy of something.

check through

To permit someone to continue onward, e.g. through a security checkpoint, after verifying their identity, tickets, etc.

gut check

An honest, reflective appraisal of one's true feelings concerning a matter of concern.

mail it in

To deliver a performance without commitment or effort, with lackluster results.

reality check

A wake-up call; a reminder.

spot check

A cursory inspection or examination, especially of a sample of something.