If you dont use a dashcam rearview mirror, or backup camera rearview...get a large convex clip-on rearview. I've used the same one on my last 3 vehicles, and cant imagine not having one. It gives a complete view of the entire backseat area of the vehicle and a great view behind the vehicle like any rearview should. To me it's much more functional than a 'conversation mirror' and lets you still use your sunglass holder. YMMV
Large convex rearview on E-Bay for $10.69
Similar one on Amazon for $9.99
Walmart for about $8