so, when should you actually think about using a service mesh?

hey everyone, ive been seeing a lot of buzz around service meshes lately, especially in microservice environments. on one hand, they seem to offer a lot of benefits like traffic management, security, and observability out-of-the-box. on the other hand, they also add complexity to the infrastructure. so, when did you find it beneficial to introduce a service mesh into your stack? what specific problems did it solve for you, and what were the trade-offs?