The 55mm f/3.5 macro, 28mm f/3.5, 105mm f/4 short mount, and 105mm f/2.8 macro are the lenses I use for macro work.
I use the 55mm f/3.5 from infinity focus to a reproduction ratio of 1:1 with an extension tube. When I need reproduction ratios between 1:1 and 4:1, I attach the lens to a bellows unit. In addition to the normal close-up and macro shots, I also use this lens attached in reverse position to a bellows unit with a slide copy attachment in order to make 1:1 or cropped copies of 2X2 slides.
I use the 28mm f/3.5 in reverse position on bellows and/or extension tubes when I need 4:1 to 12:1 reproduction ratios.
The 105mm f/4 short mount lens I primarily use under studio conditions to take close-up product shots. Using it on a PB-4 bellows allows me to use lens sliding and swinging movements to control perspective and depth-of-field. Rarely do I use this lens and bellows in the field.
In the field, I normally use the 105mm f/2.8 macro from infinity focus to a reproduction ratio of 1:1 with an extension tube. Rarely do I take a bellows unit into the field because it is bulky, too difficult to use in fieldwork, and the bellows material is susceptible to damage. The few times I have needed to attach this lens to bellows was when I needed to shoot something in the 1:1 to 4:1 repro range and I needed a little more working distance than I could get from the 55mm.