You can get a reasonable idea of how fresh or how matured your spider mite infestation is by reviewing how you discovered them. Webbing on the plant indicates an advanced issue. If you somehow noticed the bugs with no or very little webbing, you have great eyesight, and have caught the nightmare early. For me, early detection is success and mature colonies with webs, not so much. I will give it a good attempt, but need to see improvement that consistently improves. If I find mites are growing in numbers again, and I have to wait out any of the 7 days to treat again, I cry uncle. However, mites get to me, I get the heebie jeebies from this pest, imagining itchiness, with panic attacks other plants are infested too. They make me a crazy lady.
Gene's miticide is expensive for the casual grower, but is wonderfully effective. I have yet to find it on store shelves in quantities under a gallon. Ordering on line will probably be your quickest and easiest solution. Good Luck.