You get to use it but must return it at the end of the lease, unless you choose to buy it. You are responsible for any early termination charges if you end the lease early. You can negotiate a higher mileage limit and pay a higher monthly payment. You will likely have to pay charges for exceeding those limits if you return the vehicle.
Most leases limit wear to the vehicle during the lease term.
You will likely have to pay charges for exceeding those limits if you return the vehicle. There are no limits or charges for excessive wear to the vehicle, but excessive wear will lower the trade-in or resale value.