Navigating the rules around visiting the USA on a tourist visa can be tricky. Generally, you can stay up to 6 months on a single trip under a B-2 tourist visa, but how often you can visit varies. There's no set limit on the total time you can spend in the US within a given period, but the key is to avoid suspicion of living there permanently. Frequent and long stays could potentially raise red flags. Remember, the decision ultimately lies with the immigration officers at the port of entry.