A free realtime light performance optimization asset for Unity.
LightLOD is a configurable, dynamic quality adjustment utility for Realtime Lights.
Some very simple coding is required. Readme provides exact details on the 2 lines to change.
Why adjust shadow resolution at runtime?
In many cases when you have a large number of realtime lights, the performance impact of drawing very high quality shadows is unreasonable. LightLOD allows you to customize every Realtime light’s shadowResolution based on distance from the player. The idea of this is – the farther away the light, the less important the shadows are, and in some cases – can be completely disabled without noticeable impacting image quality.