I think one important conceptual idea of LilyPond is that the input
file is
mainly used to describe the music and the structure of the music, not
primarily how it should be printed on paper. Therefore, I agree with
Henning that it's much better to directly learn the correct syntax for
repeats instead of learning about \bar "|:" and ":|" which should
almost
never be used in practice.
I'd introduce bar checks before partials.
I think that bar checks may not be essential for short and simple
melodies.
In my opinion, using bar checks is an extremely useful habit. I'm
fairly
sure that a common beginners mistake is to get the rhythm wrong,
not only
in long and complicated pieces but also in short and simple melodies.
Maybe you happened to start with pieces with very simple rhythms but
I'm sure that many others will start of with some pieces with
dotted rhythms,
for example. Then automatic bar checks can save hours of trouble.
Or did you want to avoid all possible warning messages?
What do you mean?
Bar checks will generate warning printouts when you run LilyPond.
Just as it's a good habit to use bar checks in the code, it's also
a good
habit to look in the warning printouts (i.e. to look in the .log
file if
you just double clicked on a file to process it). At least, it's
good to
learn at an early stage that these .log files do exist and that
they can
be very helpful (but also confusing from time to time).
/Mats