@Seuxin - Many people are going off of the Indian & Chinese studies as a baseline for frequency. They ranged between 1 to 2 weeks before repeating needling again. If doing 1.5mm - you're going to need many days of healing before repeating again. If you go by microneedling guidance performed by aestheticians for other areas of the body (face primarily), they recommend multiple weeks of recovery. Though again, most people here are going off of the Chinese & Indian studies that performed this at a higher frequency. Most people find that within a few days, there scalp is no longer tender - and generally feels okay as if they could go right away. Although in my case and others - skin starts to peel after that and can take multiple days to exfoliate that dead skin. I wouldn't consider needling until that process is over, which for me takes up until 7-10 days after needling. You'll need to pay attention to how your scalp feels after doing this a couple times, to know what is right for you. I'd go with the expectation of doing it every 10 to 14 days or so. If you think you can do that depth/intensity on a weekly basis... go for it.