Software Engineer for 30 years here.
My standard response is "I don't know anything about that." That's almost always true. I get paid for my ability to figure computer things out, not for knowing everything there is to know about them.
Of course family doesn't take that for an answer. And honestly perhaps they shouldn't, as I don't hesitate to go to my lawyer father when I need something done with the legal system (and he doesn't hesitate to help if he can).
Honestly my saving grace with the family is that most of them are Apple-heads. Since I don't develop software for Apple products, I can honestly and legitimately claim utter ignorance for any of their Apple-related issues.
And finally I should mention immediate family. There is no logic in the universe that can save you from being free tech support for your wife. Believe me, I've tried and still have the scars. Anything tech-related that breaks in your own house not only must you fix, but you're in big trouble that it broke in the first place. If your kids have issues and you don't help, they'll just complain to her, and then you're back in the doghouse. Don't bother trying. This is just your lot in life.
One piece of household mitigation I can't recommend highly enough: If you have Windows boxes, create separate Admin and User accounts, and do not tell anyone in your family what the Admin password is. If they "need" to install something, it's gonna have to wait until you get home. I was reinstalling Windows on 3 boxes at home every 6 months before I instituted this.