I have been teaching for many years about shooting in the highest f/stop ranges, f/22 to f/32 and getting everything in focus.  Could we shoot a subject at f/16 and get it all in focus, sometimes, depends on how close we are to the subject and how much depth there is in the subject.

If I shoot everything at the highest f/stop I have no worries about getting it all in focus, so why take the chance shooting a smaller f/stop number and risk not getting it all in focus, if that is our goal. 

So now we don't have to take into account of how close we are to a subject or how much depth a subject has, we will get it done with that high f/stop.

To avoid the clutter behind subjects that will come into play when shooting at the high f/stop numbers I will always use a printed background behind the subject to cancel out the clutter.

Most know that when shooting in the highest f/stop numbers, you will get some slight softness in the details of your image from diffraction, so you don't get the sharpest image out of the camera.  But that is not an issue as we have sharpening programs in our post processing to correct the softness, that's what sharpening programs are created for.  Here is a sharp finished image of a Dahlia flower.