OnWebChange lets you set individual hour-based run schedules for your trackers. This means you don't waste your "checks per month" quota looking for changes at times of the day when content is not expected to change.
In addition, you can define your "default" tracker run time schedule in the "Tracking" section of your Account, to be used for all new trackers. And you can also apply this default schedule to all of your trackers if you wish.
To use this feature:
IMPORTANT NOTE #1: The list of run hours must be a particular format: hours must be 2 digits, with leading zero if needed, eg: 00-23; lists of hours must be separated by a "," (comma).
IMPORTANT NOTE #2: Hourly times are based in the "Europe/Berlin (CET, +0100)" timezone, so you will have to calculate any local timezone offset yourself.