How to generally decide between FACTORY and constructor?

Hi,

AFAIK, a FACTORY is a good choice when a constructor "becomes complicated
or reveals too much of the internal structure". So, a FACTORY can be used
to encapsulate it.

*But how do I know a constructor became too complex? What's the mininum
warning sign?*

So far, I take for granted that: If a constructor implements anything else
then setting values, it's a factory-elegible.

Also, when I do that, it helps me a lot on unit testing. Thus I avoid
mocking unecessary objects, for example. The same way if I need to test a
private method, so it shouldn't be private, maybe there is something
between the lines here.

Cheers,

--
Thiago Colares