I don't think many people do drop counting anymore. Most infusions are given by pump, although interestingly pumps also deliver surges in some circumstances.
Is you sayin' that I is showing my age again!!!!
Funnily enough we still use drop size when drawing up "point sized" radioactive sources for quality assurance tests. Depending on the concentration we use different size needles to give a drop that delivers the right amount of radioactivity