Mark describes it well, when he refers to a "facelift" and draws the comparison to cars and model years. A couple of points to add:

-- With the Carrera facelift, from first execution to second execution, Heuer also changed the hands, so that they go from plainer hands to hands with black inserts. Some collectors might prefer the clean lines of the earlier hands; others may find the updated hands a bit sportier . . . it's all a matter of personal preference.

-- Heuer seems to have been very rigid in having the style of the hands follow the style of the dial / markers . . . so both seem to have been updated at the same time.

-- As contrasted to cars and model years, Heuer may have been willing to use the leftover parts from an earlier model on current production of the later model, so the model years and updates are not as distinctive / well-defined as on the cars. There is also the issue of watchmakers using later hand on earlier watches when they came in for servicing, which has resulted in a lot of mismatches between hands and dials.

Jeff

+++++++++++++++++++++

: Basically, Heuer gave the first generation Carrera a
: "facelift" partway through its lifecycle, in much the
: same way as carmakers do to keep a model fresh.

: First execution 2447 N, with the features you described on your
: watch:

:
:

: And second execution:

:
:

: Personally, I find the second execution loses some of the Bauhaus
: simplicity of the first and some of the additions are just for
: decoration not function, but a lot of people like it as it
: introduces "panda" dials (i.e. where the registers and
: dial have contrasting colours).

: How much you wind it depends on how you wear it. Many of the people
: here have multiple watches, so an individual watch is often left
: to wind down completely. Whilst you wouldn't want to leave one
: like that for too long for fear of something seizing, it doesn't
: do any harm. Equally, the watches were designed for daily wear
: (rather than us weirdoes with many watches ;) ), so keeping it
: wound shouldn't present too much of an issue either. The Valjoux
: 72 movement is a veteran movement and had been refined over
: decades by the time it was used in the Carrera.