I used to check things multiple times a day, then I realized that I didn't have to. With the size of my res things stay very stable. I expect a slight PH swing over the coarse of a day or a few days, its pretty normal and allows proper nutrient absorption across the spectrum. The ppm change slowly in my res over a few days as well. I realize that as the plants drink there are different amounts of nutes left in the system, and that we can't tell how much of what there is. However I don't think it matters if the plants are healthy. I also run all my flower plants on the same res no matter if they are new clones put into flower, or plants that will be harvested that same week. The plants seem to do a very nice job of drinking what they want, and growing great. I also run a bunch of different strains like JD does, and I find that its pretty rare that I have one that doesn't like my room. I would never claim my room is the most dialed in, but my garden and products that come from it speak well enough for themselves.
Anyway theres lots of different ways to reach the same goal. What will work best is up to each of us using them. I stopped using soil because I didn't want to go buy it, haul it, and dispose of it. Sadly I have to operate incognito where I"m at, and its much easier to do that with my hydro system. Both methods grow amazing cannabis though.