The Tips in detail

 "Adding attenuation-ranges to your lights speeds up rendering."

This is because the rendering engine does not have to calculate the lights areas up to infinity (in worst case). Although using attenuations might not speed up your renderings noticeable in every scene it will do so in many cases.

Decay continues to calculate dimmer and dimmer values as the distance of the light throw increases. Attenuate at least the end of the light to eliminate unnecessary calculations!

Using "inverse" or "inverse square" will make it necessarry to increase the light's multiplier or make the color of the emitted light brighter. When making the light's color brighter make sure you do not exceed the allowed color-values for the media you are intending to use, especially if you are out to render to VCR-tape. Also refer to "Using lights with fall-offs makes your scenes look more realistic." for more information.