I have a container garden with plants in close proximity, so when I found what I was told were spider mites on two small dahlias, I quarantined them and started spraying all my plants with Neem Oil every other week. The dahlias didn't make it, but I have continued spraying every 2 weeks. My plants all look healthy and pest-free, and I'm wondering if I'm just making work for myself.
A related question: if I *am* going to continue spraying, would soapy water work just as well? I have read so many different ways to make an effective pesticide with soapy water, like add vinegar, add oil, use this kind or that kind of soap, that my head is spinning.
Thanks for any feedback.

Just saw your Q. Hope u other plants made it. I've had results with 1 Tbl. Dawn to 1 gallon water. Mites are tuffies. Be diligent ! Spray undersides and tops (if present) of leaves every 3 or 4 days. It will take several doses or more.