Intensive cron jobs or scheduled tasks
In this article I'll quickly touch on why intensive cron jobs or scheduled tasks can cause problems on your account by leading to excessive resource usage.
What is a cron job?
A cron job is a way to setup a scheduled task on a Linux machine. This lets you run tasks on your website without you having to actually be present to initiate the task. You can read more about how to run a cron job for more detailed information on cron jobs.
How often is considered intensive?
Typically you wouldn't want a cron job that runs every minute, sometimes even as often as every 5 minutes, or every 10 minutes can cause problems. It's really all going to depend on how intensive the task is that you're attempting to run.
In some cases you can also automate and schedule activity in a cron job to reduce usage, a good example of this is by disabling the wp-cron.php in WordPress. WordPress has it's own built in scheduling script, and by default it runs on every page request, using a cron job to do this instead at a set interval can help keep the overall usage down.