There is no definitive answer. If your pictures are looking good (sharp), then there is no need to check.
However, after travel, mechanical shock, before a very critical shoot with narrow DOF, in a very different environment (temp, elevation, humidity), it might be wise to do a quick check. Or maybe after the first month.
You can do a quick check by taking a few test photos of LensAlign, and just check the ruler visually (no need to use FocusTune at this point). Chcek the test pictures to see if the DOF looks balanced between front to rear of the zero-line. iI it looks good there is no need to test further. If it looks like it needs some adjustment, do a shortened adjustment routine, shooting 6 pictures at AFA settings just around the existing setting. For example...
- If the camera is set to +10, and when you do a quick check, the DOF looks like it is too much to the rear, then the AFA adjustment would probably need to be set more to the minus (-) end of the scale. So if +10 were the setting, do your test shots at +6, +8, +10, +12, just to cover the likely range of possibilities. Run through FocusTune and determine the proper setting.