Have you had a history of grub infestation? (But not just the occasional grub; almost every lawn has few, and even one or two per sq. foot is not going to cause any problems..) If not, I would avoid preemptive use of pesticides.

Insecticide is the worst thing you can use on your lawn (after fungicide), because it kills out an entire class of beneficial microbe in the soil - the microarthropods. Yes, avoid the use of insecticides as much as you can.

Grub infestations are usually predictable. If you have a swarm of beetles around your porch light in May or June, then you have a better chance than most of getting a grub problem. Those beetles lay eggs in the soil which hatch and eventually become the grubs. Your lawn should be able to tolerate up to a dozen grubs per square feet. If you would like to do that research right now, you can. If you have a lot more than a dozen per square foot, then you can apply a grub killing product. Otherwise, join the majority of us who rarely-to-never use insecticide.

thanks