Door swap question

If you're swapping doors, or just taking them off for paint, are you better off taking the hinge off the door or the body?

Is one way easier to align than the other on installation?

Depends in the door. 

Miata: door side

64 El Camino? Body side

Gmt400? Pin connection 

Well specifically my ranger rear doors. But I was hoping there was a general answer.

I did the miata by the body, cross threaded the last bolt, and don't want to repeat that mistake.

Depends a lot on the chassis design.

I prefer to do chassis side, and have the fender off if possible.

Which hinges are the least worn out?

That is what I would base the decision on,  but I deal with exclusively old cars 

I did body side on my Miata a few times. This was for installing then removing the frog braces. 

Alignment is easier after if you can just pull the pin.

Z4 has a pin. I recommend only buying cars with a pin in the hinge.

Side note: the '07 door's airbag would not talk to the '03 airbag computer.

Which bolts can you get at?  Most, you have to leave the hinge on the body, unless you have the fenders off.  Then, body bolts are easier.

Best solution? Buy a fwd Volvo.  Loosen the set screw, undo the electrical connector, lift door off pins.

In reply to Streetwiseguy :

Volvo are not alone in their door hinge simplicity.  Besides the aforementioned newer GMs, and Jeeps, VW havefor a long time used a single bolt per hinge to hold two halves of a hinge together. Two bolts and the door is off.  The downside is that you can't adjust the door, VW design hinged (sorry) on perfect manufacturing and who cares what happens after the fact.