Watering in Fertilizer

When watering in fertilizer I wonder how frequently do you use the fert recipie as opposed to just plain water? I imagine that it varies to some extent based on the strain. But in gerneral, for a soil grow, how often would you water in the fertilizer? The package says every time, but I know better from what I have read before. Also when using something like liquid karma, what is the best way to add that to a scheduel? Directly mixed with the fertilizer and water? Later on in veg I suspect that cal-mag plus will also be added, so again, do you just go with what is on the bottle and mix into 1 batch? Thanks for the input in advance!

I fert once a week in soil and use the calculator on my nute manufactures site. Take the info from the calculator (AN in my case) and adjust for strain tolerances and you're good to go. Leave at least 10 days for flushing at the end.

I've read on here that cal-mag isnt really needed in good soil with dolomitic lime mixed in and can cause other issues if overused.