I think another big issue is to check the plastic all around the carseat, look for any weakened spots or stress spots they look lighter in color like when you bend plastic and it turns whitish.. those weakened spots come from use and heat of being in a car, and can compromise the integrity of the carseat. But we will be reusing ours from dd2, got a new one from dd1 to dd2 but that was only because we got a new stroller and wanted the right kind of carseat to fit it.. and we don't keep it in the heat, it stays inside in a closet.. we will also check it thoroughly before use. But same as p.o., dd2 hated her infant carseat and we ended up putting her in a convertible by 4 months of age, so I don't want to buy a new one if we just have to go buy a new convertible one also!