Depends on your plant health.
I personally have a very agressive schedual myself. I spray once a week for prevenative bugs, and once a week for nutrition.
I usually alternate preventive sprays,
Spinosad one week, Caterpillar killer the next, neem the next. The Cat killer doesn't need to be applied until the last full moon before August, then apply up to the week of harvest is safe. I also release lady bugs, lacewings and praying mantis for natural control.
For foliar nutrition, this really depends on your plants, and how healthy they are. Do you have soil tests? Sap analysis? ACT foliars will help with PM. I really like foliar sprays of sea shield (fish) and rejuvenate (molasses and other microbes) from American Eco Agriculture. If my soil was perfect, and my plants look healthy, I might skip nutritional foliar sprays all together. Hope this helps.