make sure hook cron is only run once a day setting I'm building a hook_cron in my module but I actually don't want it to run at a maximum of once a day.
Is there a Drupal setting for this or do I need to check when the last cron was run and see if that was at least 24 hours ago? How do I do this?

I'm using drupal 7
I would check the implementation of hook_cron() in the Examples module.

The exact implementation is here, it's pretty straightforward!

Basically, you're setting the next execution time (in the example code as cron_example_next_execution) of your cron run as the very last step in your hook_cron() implementation, and then checking it as the very first thing.

If the variable doesn't exist, then cron will fire off your task, and then set it!