I don't go outside for social reasons, but I go out often enough. Sometimes for work, school, family time, personal shopping, etc.
There was a point where I would only go outside if I was forced to, such as going to school (grade school so my parents were bound by the law to make me go) or to the doctor. Otherwise I'd be too scared and refuse to go. Social anxiety is fun lol
Honestly if you have SAD, it's not worth beating yourself up over how often you go out. I go out a decent amount but it's usually very stressful because of the anxiety. It's important to get controlled exposure so that eventually you can actually enjoy going out. What helped me most in starting to go out again was doing short bursts. Like sometimes I'd walk home from school, and once I was comfortable with that, I'd take different paths or sit on a bench for a little bit. It always feels scary and like people will think you're totally nuts, and there were a few times where people would look at me weird since I was a grade schooler with a giant backpack wandering around and staring at the sky in complete fear while crying lol but eventually, you realize that no one actually cares that much about what you're doing. The physical feelings associated with anxiety start to go away, and then you'll be going outside because you're bored and want to take a walk. And people will just look at you and move on, because you will seem like any other comfortable person living their life.