You probably want to hear a fist number. But we'd have to lie, because the answer depends on what you want to do.
In large-scale farming, representative measurement points are suggested to you based on public soil data, remote sensing, and plant growth modeling. Of course, you can change that and choose installation points and the number of sensors based on your own experience. Because in the end, you know your land best.
Example arable farming: The home farm of our founder Andreas is located in the low mountain ranges and has 170 ha LN, of which 145 ha are AF and the plots are divided into 3 districts with 4 main topographic moisture classes. The soils are partly deep, but partly very shallow. For each plot we recommend 1 CLIMAVI weather station and 3 CLIMAVI soil sensors to measure respectively the wettest, driest and medium topography class. In total 3 CLIMAVI weather stations and 9 CLIMAVI soil sensors.