Depending on how spondylosis affects the parts of your spine, it may cause spinal instability. That means that the parts of your spine (review the anatomy section for more details) aren't working properly to control your movements. With an unstable spine, you're more at risk for neurological injury (injury to the nerves). To address this instability, your doctor may recommend you wear a brace for awhile.
Long-term bracing isn't usually recommended because it can cause the spinal muscles to weaken. It's better for you to go to physical therapy to learn how to strengthen your muscles so that they better support your spine.
Your doctor will decide if bracing is a good option for you, what kind of brace you should wear, and how long you'll need to wear it. With a brace, it's absolutely critical that you follow the doctor's order exactly for how and when you're supposed to wear it. If you don't, the brace won't be as effective at relieving your pain and providing support.