When do you need to buy a license plate sticker?

You need to buy a license plate sticker when you renew your vehicle registration, which typically occurs annually or biennially, depending on your state or province. The sticker serves as proof that your vehicle is registered and that you have paid any required fees. It's important to purchase and display the sticker on your license plate before your registration expires to avoid fines or penalties. Always check your local regulations for specific renewal dates and requirements.