As an example I'll talk to you about the differences bewteen three versions of my FIREPLACE BELLOWS:
SUBJECT A:

SUBJECT B:

SUBJECT C:


Let's see the following aspects in all three models:
EFFICIENT USE OF PAPER:
I think the more efficient use of paper would be in Subject A, since with a 2 X 3 paper I can fold a functional bellows. After that one comes the Subject B which uses a 2 X 5 paper and finally Subject C which is made from a 1 X 3 paper. I need twice as much paper for Subject C in relation to Subject A, that isn't efficient use at all!
USABILITY:
All three are quite effective for blowing (not a pun) and all three versions have a problem with the handles: Subject A doesn't have handles. In Subject B, most of the bottom of the bag isn't attached to the boards so you have to hold the first and last pleate of the bag with your thumbs for a more effective use instead of using the handles.
In Subject C the bag is attached to the boards even to the handles, so you can use the handles in the small toy version. The problem is when you use one that's of the same size as a real fireplace bellows. The weight isn't balanced so it's hard to use it by holding the handles; it's a lot more comfortable to place your thumbs in the first and last pleate of the bag (like in Subject B).
This is the way I hold both Subject B and C:

RESEMBLANCE REGARDING THE ORIGINAL OBJECT:
This is how a real fireplace bellows looks like:

Subject B is the one that resembles the original object the most. Subject A doesn't have a color change nor handles. In Subject C the bag goes all the way to the tip of the handles. Besides that, the sides of the bag aren't attached to the boards so you can see from the sides this long space between the bag and the boards. None of those things happen in a real fireplace bellows.
In Subject B the bag ends where the handles begin, and the sides of the bag are effectively attached to the boards, just like in a real fireplace bellows

In conclusion, Subject A is better at efficently using the paper, Subject B in assuming the appearance of the original object, and Subject C is a little better than the others in it's usability. How do I choose one in that case? Which one do you prefer taking into account my comments on each one?
Like I said in the beginning, this was just an example. So I would specially like to know how do you choose the oficial version of one of your models as you make small changes between each prototype?
Thank you!
Edit by Moderator:
All bold and oversized text changed back to normal. Are you mad shouting at us like that?