On my old 1998 Jeep Grand Cherokee (see sig for a pic)
Yakima, 48" bars, anklebiter bike racks, snowboard/ski racks, custom made hilift jack mount
Just the stuff the racks were made for, once a wakeboard in the snowboard rack, and christmas trees

Bike racks, probably once ever 2 months (didn't ride much after I bought a dirt bike, engine > legs ) Snowboard racks once a month in winter.

 

1) '91 runner
2) stock rack
3) camping gear

 

91 runner...no racks but thinking about adding a stock OEM rack.

 

1) 4Runner '95 SR5
2) Wilderness Safari Rack
3) Loads of stuff gear wise.
Accessories include: (wilderness acc.) Shovel Bracket, Hi-Lift Jack Bracket, Yakima Bar mounts, Light Brackets: (Rackmounts) Rod Mounts, fishing rod rack: (Yakima) load bars, Big Powder Hound Ski Rack.

Additional Questions
1) All miles on road ~15K a year
2) all miles off road
3) As much as possible. 10-12 weekends a year of camping/fishing trips with rack fully loaded.

Comments on Rack: I love the setup. Garvin (Wilderness) has all the accesories you could ever need. Rack is steel, extra weight is nothing. Fully loaded it's real sturdy. I can use the rack to support my weight climbing up to load it. All in all 5 out of 5 stars IMO.

Pics>>

 

have 94 4runner, have stock roof rack, carried car top carrier (vacations), sheets of wood, ladders, furniture, and probably other things I forgot about since I had the truck for 10 1/2 years.
By the way, I think you meant to use there and not their. (being a SCHOOL project and all)