I think it depends on your case, some people it only takes them under a year. If you have something pending with the courts, it will take 2-3 years. Specially now that courts are closed. I'm going on 1 year and 2 months of the ongoing process. So far the only thing that has been approved is my family petition (I-130). Application to adjust is on hold since courts are closed. If your case is straightforward, overstayed, married US citizen then you should be 1 to 1.5 years. But if pending with courts, expect 2 to 3 years.