According to Mario Rios "if you're not lifting over 275 on deadlift or squat you shouldn't even be getting near a belt."

But this is just an arbitrary guideline based on nothing.

Does this standard apply for 200 pound men the same as it does for 100 pound women? What about 20 year old's vs 70 year old's? So my 68 year old 120 pound mother shouldn't put on a belt until she can squat 275lbs, which means she'll never be "ready" to wear a belt according to Coach Mario.

But a 20 year old 200 pound dude who I could potentially have squatting 275 in a month, will be "ready" to wear a belt basically right away. This makes no sense.

You learn how to brace intrinsically, and then if you want to use a belt to augment your training and bolster your progress then buy one and LEARN how to use it. And that is an important part to note as well, because there IS a learning curve to belt usage. Not everyone will benefit from it right away because it often takes time to figure out how to use the tool to its maximum benefit and really gain large IAP increases from it.