You should see a physiotherapist if you have knee pain that doesn't go away, especially if it affects your daily activities. Even if you're young and active, starting with physiotherapy instead of surgery can often be a good option.
Most people with a meniscus tear improve with physiotherapy, and surgery is not usually needed. For younger individuals, it can take about 4 to 12 weeks for a mild meniscus tear to get better, while for older individuals, it may take longer. So, seeing a physiotherapist early on can help with the recovery process. If your symptoms do not improve your physiotherapist can determine if further investigation and/or treatment is needed.