I have more than a dozen special commands for splitting to multiple n*m windows filled with different types of buffers or transposing existing window splits; I occasionally need a split into 4x4 or 5x5 or even more windows to quickly/visually find the shell that logs something of interest to me. It is not neccessary, really, but occasionally helpful. I often switch between 1x3, 2x3, 2x4, or 2x2 layouts that it was worth putting in the time to organize all these splits and then adding some more felt easy and useful. My three different main monitors (home/work/laptop) often require different optimal splits and depending on the focus mode, fonts, or the presense of a browser window I may again need differnet splits. I often find it helpful to have follow mode on a 1x3 setup either a single document to have focus over a larger context. The main reason for all the splits, however, is managing several dozens of shells or code files.