I had some grow store dork tell me I needed to “up my game” with an electronic meter. I’m like brother everyone and I mean everyone has a story where they fucked up their plants from a way-off uncalibrated meter. The drops are never as ACCURATE, but they’re never wrong. Do you really need to know if your pH is 6.1 or 6.13? I bought a 250ml bottle of the reagent for like $30 and that’ll essentially last me a lifetime.
EDIT: OP, if you’re taking the time to pH soil, you might as well go soilless with liquid hydro nutrients. Far more consistent, IMO easier, and better yielding, with less chance of contamination. Soil is more of a “feel” type discipline. If you have issues in soilless with hydro nutrients, they’ll be much easier to correct. Go mixing in a bunch of bat shit, ground crab powder, worm castings, and oyster shell and you have a bunch of unaccounted-for-variables. Pro-Mix HP is good, hydro stores sell a million other options. Tupur, for example. Some people take their organic soil projects to Rube-Goldberg levels of work. I like easy, reliable, and effective.