If you arrive to the airport early, you will allow the security agents more time to search your luggage if necessary. Most airlines recommend you arrive two to three hours prior to your flight, depending on if you're flying domestic or international. By arriving even earlier than the suggested time means more leeway just in case you were selected for further search. If you have more time you can stay with your bag throughout the entire check-in, enabling you to unlock your luggage for agents if they request to open it. After the agents are satisfied with their search, you may lock up your bag once again.
In some cases, your luggage may be searched again after the initial check. If you're not present for this search, security agents may end up cutting your lock. You may purchase a TSA approved lock for your luggage. This means that instead of cutting your lock, agents may just use a skeleton key to open it. These approved locks start from $10. It's much cheaper to purchase the lock online or at a store prior to your trip than it is to buy it at the airport.
If you're not traveling with anything valuable, skip locking it. Some airports and airlines even suggest forgoing the locks to allow for speedier check-in. Security agents can simply open your luggage, shuffle through, and close it again without waiting for you to unlock it or for them to find their skeleton key. If you decide to not lock your checked luggage, make sure to keep your more valuable belongings in your personal or carry-on items. This includes jewelry, important documents, medicine, and other items that you can't risk going without on your trip. Also, keep your cell phone and laptop with you even if you don't plan on using it during your flight.
