How to organize an extensible and reusable object? I'm modelling an aircraft landing gear. I have currently done the wheel part only, but as it's just a piece of the whole landing gear, I would like to have it as a "base" object that can be used in many configurations. Some examples (not mine) are front landing gear


(source: foundation3d.com)  

and wing landing gear


(source: aircraftrecognition.co.uk)  

As you can see, the wheel itself is pretty much the same on either, but the part that connects it to the airplane can be very different depending on the configuration. 

Should I create the different gear configurations by duplicating the wheel itself and editing? Or are there better methods where I can have only one wheel model (like an array modifier)? It seems to me the multiple objects approach (wheel, gear) is clumsy as I can't control how exactly the wheel connects to the gear.
Alt+d (Duplicate Linked) might be what you are looking for.  By duplicating this way, when you edit one of the instances then all the others will be changed as well.