I think the biggest difference comes down to why someone is doing a certain behavior and how much it impacts their life. Everyday habits are usually things we do because they’re helpful, comforting, or just part of a routine. But with OCD, the behaviors are often driven by intense anxiety and feel necessary to prevent something bad from happening—even if logically, the person knows it doesn’t make sense.
Another big distinction is the level of distress. With OCD, the compulsions can feel intrusive and exhausting, making it hard to focus on anything else. If skipping a habit makes someone uncomfortable but they can move on, it’s probably just a habit. But if skipping it causes overwhelming anxiety or panic, that’s when it might be something more.