The single most common fear I hear when a parent is about to move in is some version of: “Will this cost them their government benefits?” It’s a good instinct — the benefits are the floor a low-income parent stands on, and wrecking that floor by accident would be a genuinely expensive mistake.

Here’s the counterintuitive truth that should lower your blood pressure: the act of moving in — the change of address itself — touches almost none of it. What actually moves these benefits is income, and specifically whose pocket money flows into. Get that distinction straight and most of the panic evaporates.

When a parent needs to move in, the housing question usually gets framed as a feelings problem — where will everyone be comfortable, who gets which floor, will it feel like an intrusion. Those matter. But underneath them sits a six-figure capital-allocation decision that most families make on gut instinct and regret later.

There are really only two serious paths: build a self-contained unit into the home you already own, or sell and buy something bigger with a suite already in it. This post is the cold-eyed math on both — the build costs, the two federal tax credits that quietly tilt the whole thing, the friction costs of trading up that nobody budgets for, and the optionality one path gives you that the other doesn’t.