Until you get the intuition of the soil, I would look at the plant itself. A plant drying out or in need of a good watering should show visible signs. I would google "thirsty <species>" to look for images of what a thirsty plant looks like of your species. In Monstera, google says a thirsty plant is one that is droopy and has yellow/"dry" spots on leaves that aren't near the bottom (ie. aren't being discarded as normal growth).