quoted from bukboy:

technically, a phrase is defined as a small group of notes which makes up a single musical idea. whereas a section is made up of phrases, i.e. a section is made up of a number of musical ideas.

practically a section which is made up of a question and answer, is made up of two phrases, i.e. a question phrase and answer phrase.

In one example, in "enjoy the silence" by depeche mode, in the chorus which goes
A = "All I ever wanted" B = "All I ever needed"
C = "Is here" D = "In My arms"
E = "Words are very" F = "Unnecessary"
G = "They can only do harm"

AB CD EF G all make up "phrases".
A & B are similar motifs
C & D are simlar motifs
E & F are also motifs . (i.e. motifs are repeated ideas)
but the whole that is made up of 4 phrases is an 8 bar "section". A "section" is defined as one complete large idea. (sections are also repeated in much the same way that phrases and motifs are, but on a larger scale)
A section can be made up of any number of phrases but in the above chorus it was made up of 4.

NOW that a "section" is defined, there are different kinds of sections, balanced, unbalanced, and symmetrical or unsymmetrical.

Balanced section is one where the number of phrases is even(in most cases) or when the phrases add up to an even amount of time, in the above example the section is balanced because ABCD is balanced by EFG (G is twice as long as the others)

An Unbalanced section would be one like ABCDEF (without G to balance)

A symmetrical section is where all the phrases are symmetrical (i.e. they are all just as long) So the example above is not symmetrical.

NOW balance and symmetry are used for different reasons.
balance is used to give sections a feeling of completeness, whereas "unbalance" is used to thwart the listeners expectations(hit them with a new section when theyr not expecting it, or delay the next section so that it builds up tension in expectation).

Symmetry/unsymmetry on the other hand amounts to monotony/interest, so if want to express a monotonous effect then symmetry is the way. Or if u want interest then make ur sections unsymmetical.

Now to finally get to your question. In psy, breaks act as punctuation for sections. not as entities for their own sake.(although if u really want to make a contrast I suppose u could do that once or twice)

So now my answer is - design your sections based on what effect u want them to have, then "punctuate" them.

I hope this is helpful.