Correct usage "i.e." and "e.g." ?

[John Renish <John_F_Renish -at- NOTES -dot- SEAGATE -dot- COM>]

FWIW, the famous Sun style guide permits both these abbreviations. E.g.
means 'for example' and should always be used without 'etc.' or 'and so
on'. I read 'etc.' or 'and so on' as, 'and I can't think of anything else'
in the best of cases; such qualification makes no sense with 'e.g.' or 'for
example' because an example or list of examples is never meant to be taken
as exhaustive. There is nothing wrong with writing 'for example' if your
house style is to avoid abbreviations or just abbreviations of the literary
sort.

It is difficult to justify _ever_ using 'i.e.', though, because if you
write it right the first time you don't have to explain what you mean.
Let's take the preceding sentence as an example:

WRONG:
It is difficult to justify _ever_ using 'i.e.', though, because of the
possibility of the correctness of initial expression; i.e., [or 'that is',
if you prefer] if you write it right the first time you need not explain
what you mean.

RIGHT:
It is difficult to justify _ever_ using 'i.e.', though, because if you
write it right the first time you need not explain what you mean.

John_F_Renish -at- notes -dot- seagate -dot- com, San Jose, California, USA
My comments represent my personal views and not those of my employer.
"Ol' Diz knows the king's English. And not only that, I also know the queen
is English."
--Dizzy Dean, baseball great, responding on air to a letter from a listener
who said he didn't know the King's English