> Quote - If you put AO in nodes with Indirect, consider removing the AO from the eyelashes of human characters. Huge rendertime hit for AO on lashes with IL

AO in shaders with indirect light can take a loooong time. Avoid it if you can. What's happening is that the indirect light is tracing a couple hundred (or thousand, depending your settings) rays for every red dot in the prepass to find out the light coming from the environment. To get that, it has to evaluate the shaders on every surface it encounters - and AO again spawns extra rays. So things can become very, very expensive.

Indirect light will skip AO on lights, as AO is the fast approximation of what indirect light is doing for real. In shaders, however, it gets evaluated as it could be used for anything - not just plain occlusion, you can make some really cool procedurals with it, like rust in corners.