From other people, such as physical attack? No. I would never trust the safety of my life with a magick protection or guardian spirit.
Although its always nice to include spiritual protection along with good decisions and safety precautions. For instance some believe in carrying medalions of angels, deities, saints, etc for this purpose. A Saint Christopher medalion has been passed down to me in my family, always carried by men given to by a woman. I gave it to my husband to keep in his pocket. Christopher is believed to protect against accidents and every person that has ever held this medalion in my family (including my husband) have experienced accidence that could have ended in severe injury or death, yet miraculously left them unscaved or only mildly injured.
From spirits and negative energy/magick thrown or given off by people? Yes. Servitors or simply thoughtforms.
If you do go down that route I suggest destroying it every week and remaking it. Also maintain it every day.
The best servitors are those attached to a physical object, ideally a piece of paper kept in a safe place that can be torn up to disperse the energy of your thoughtform. What happens to servitors when not maintained and destroyed and rebuilt is that they eventually gain an intellect and personality of their own. Since they do not have souls like we do, their energy is suseptable to being tainted by surrounding energy. Negative energy can attach to us in our daily lives and they are no different. They can become overly protective (like a wild dog), aggressive, or even malicious. So be sure to keep a good system going and make it a daily routine to sense it, and make it a weekly routine to fully destroy and rebuild it. If you do that, you should fine.