Almost anytime is a good time to apply Cinderite. But if you have a lot of snow where you are located, I would recommend applying before the snow comes. This will give it time to work itself into the soil and start balancing out the soil fertility.
It's a one-time application as long as you apply it in the right amount.
You can apply 1 lb now and another lb later if you want.
This is how it helps with keeping most pest bugs away:
Cinderite’s mineral composition, paramagnetism and benefits to soil structure enhance plant health and immune response. Insect pests can’t properly digest healthy, vigorous plants due to the complexity of proteins, fatty acids, etc. Instead they select and feast on plants that are deficient in minerals, moisture and living soil.
For example:  In the instance of a vital mineral deficiency, a plant may seem completely healthy to us, but an insect pest can detect that deficiency due to cellular degeneration in the plant. When a plant rots, even on the cellular level, it releases substance such as ethanol which the insects are attracted to. The entomologist, Dr. Thomas Dykstra, explains this phenomenon in an interview on the Regenerative Agriculture Podcast (http://regenerativeagriculturepodcast.com/how-insect-pests-identify-unhealthy-plants-with-tom-dykstra).
It is also speculated that paramagnetism directly influences the behavior of insect pest as they determined where to feed, but not enough peer-reviewed evidence supports this idea to make it a valid claim. We hope to contribute to more discoveries on paramagnetism and insect behavior.