The telescopes generally do not guide by default on exposures of or less than 120 seconds on most systems during optimal conditions. If the weather is sub-optimal with light clouds, winds, humidity, etc, it will occur earlier.
Telescopes with External guiding will guide more often than systems with internal guiding. Systems on Fork Mounts or Planewave 200HR Mounts, will have guiding completely disabled due to the pinpoint accuracy of the mounts.
To determine which type of guiding your system of choice is using, check the Telescope Information Page. Clicking any of the numbered links on this page will take you to a detailed explanation of the parts and settings for each individual telescope.