Thanks for the tip. Actually, I was referring to focusing on stationery subjects. Its just a personal habit to make sure focus is spot on, after which, if focus is still in doubt I will quickly change to focusing alternate target(s) at the same distance away. I strongly dislike the continuous mode (just like I don’t use the Auto exposure mode) because I like to retain, exercise some form of “manual” control over what I do. On many occasions, with the grip in use & my left hand positioned thus, I accidentally moved the switch to “C”. As a consequence, after I lock focus on my subject (on the eyes for portraitures) & reframed the picture, the focus shifted/changed, resulting in so many OOF shots without my knowing why, until very much later with regret. You can try this focusing/reframing using the longer focal lengths & understand what I mean. For tracking moving objects like racing cars, its another matter & yes the "C' mode is invaluable; its almost instantaneous for the 24-120 too, even in low light. Even then, with center focus point & continuous focus, the subject is in the center of the picture & this is not always preferred.
Cameras & lens can & do focus very fast & very accurately but if the target is not ideal, it still result in misfocus, as is so often the case. Some people I find blame their equipments but many times, the photographers are responsible
For fast moving subjects, I resort to other techniques like panning (also to give the feel of movement) & crucially to this key skill called Anticipation, & locking focus on fixed points, just like in those days where autofocus does not even exist but great photographs were still obtained! Cheers!