Thinking about buying a house? The 30 rule helps you figure out how much home you can actually afford so you don't get in over your head. It's simple: don't spend more than 30% of your monthly income on housing costs, including your mortgage, taxes, and insurance. This guide breaks down exactly how the rule works, why it matters, and what you need to watch out for when buying online. Get real tips to keep your home purchase stress-free and within budget.