I usually check a few times a year, and then try to use the lesser used lenses.

For Cameras, my usage was 66% Canon 6D & 30% to the Sony A6000. The other 4% went to the Canon 7D (Sold in July).

As for my lenses,
Sigma 20 Art - 26% (skewed due to a time lapse)
Canon 35 IS - 17% (my walk around lens)
Sony 50 OSS - 16% (my walk around lens for A6000)
Tokina 16-28 - 12% (sold to get the Sigma 20 Art)
Tamron 90 VC - 8% (purchased in October, used primarily for a wedding)
The other 21% is spread across 12 other lenses!

When I go on any sort of trip, my kit is usually the Sigma 20, Canon 35 IS, a macro and a Tamron 70-200 non-vc all on the 6D.

Overall I am happy with my kit, although looking ahead, I would like to upgrade my Canon 50 1.4....looking at the Tamron 45 or Sigma 50 or the Canon 45 TSE. I also would like to go wider than my Sigma 20, but really can't justify the Sigma 12-24.

Very good post Brant!