In B2B SaaS, the most effective segmentation usually comes down to firmographics (company size, industry), behavior (how often they use your product, key features they rely on), and value metrics like LTV or plan tier. Those three together give you a clear picture of who actually matters. From what I’ve seen, usage-based segments are especially powerful because they show real intent, not just assumptions, so you can tailor onboarding, upsells, or support more accurately instead of guessing based on company type alone.