My regular program is to take soil samples over 5% of my customer base each year. These are drawn randomly from a map. That way, I can map out pH, P, and K trends across time and across locations. I just so happens that most of the lawns I treat on the north side of town have a pH of 6.8, but the ones on the south side of town are closer to 8.0. So, I only make the sulfur applications in the south side routes, not the north side routes.
I've only done about 5 tissue tests in my 30+ yrs in the business. All of them were from clients who specifically requested it. For managing lawns, I don't see a whole lot of micro deficiencies. I think its more popular in golf because of the sand based rootzones, the low fert programs, managing 'on the edge', and the high expectations of the clientele.