In an effort not to make our house become an indoor junk yard, I heated and A/C'd the garage.
It's much nicer working an an environment that is climate controlled, and it wasn't all that expensive, either. It's an electric A/C and heating unit, that mounts in the wall, and only requires a 220vac "dryer" plug for power.
I insulated the garage walls, and rafters, and put weather seals on the door. Works great, and is independent from the household heat and air.
During the summer I keep the garage at about 75 degrees, and during the winter at about 68 degrees. During the fall and spring I simple open the doors.
I have lighting in the ceiling (for when the door is closed), and at the top of the walls around the perimeter of the garage for when the door is open.
I've always figured that good lighting, enough room, and controlled temperature were all "musts" for a garage.
On top of that, I don't want to argue with the wife, or ruin the rugs, floors, furniture, walls, or window and door molding with grease from parts and dirty hands.
The original cost of outfitting the garage, was a bit of a set back to working on the cars, but in the long run, the time and expense saved from not having to clean, repaint, or replaced rugs, and such, turned out to be a time and money saver.
Not to mention that the place is always presentable when guests come over.
