The mirror modifer is great, but is there any mode that allows MOSTLY symmetrical work?
IOW, a tool that asks “Is there a vertex corresponding to the current vertex on the other side of the mirror plane? If so, transform with the current tool.”
Like, imagine you’ve got a spaceship that is 90% the same/symmetrical on both sides, but one side has a sub-assembly that doesn’t exist on the other side. TMK, the Mirror Modifier would generate the unwanted sub-assembly.
If the Mirror Modifier be limited to specific Vertex groups/Face maps, that would do the trick I think.