At one time Pa required inspections every 6 months, it's annual now. Not sure of the politics but rust is a real problem, brake lines, frame, suspension, etc. My dad had to retire a 98 Chevy truck 3 years ago for frame rust-through right before he retired from driving. You dry climate guys can't imagine brake lines rusting through, or frames, or rear diff covers.
It's actually a great deal, for $15 a mechanic checks brakes, suspension, steering, tires, glass, body/frame integrity. Of course it's important to have a mechanic you trust.
Most people NEVER knew how to maintain a car, it's a bit of insurance for the rest of us.