It takes some time for soil ingredients to absorb moisture. Peat is slow but then holds water well.
With about 1/3rd peat in the mix, and after that initial soaking, I can set it in a basin of water right up near the top of the plant containers. In as short a time as 20 minutes, the soil mix has absorbed to the max.
The containers are then set where they can drip whatever is excess. A few days later, they are back in the basin. Larger plants are able to draw water out more quickly. Tiny seedlings don't need to have that bottom watering very often. Species vary in need.
Experience brings a "feel" for the weight of the containers and watering needs. Really, there is quite a lot of difference between dry and wet soil mix. I once did some weighing, thinking that it might be helpful. I don't know where or when I mentioned it on TEG. If memory serves, what I thought of a dry container weighed 1/2 of a container with fully saturated soil mix. That seemed to be a safe zone: full weight to 1/2 weight.
Steve