Time has a big role in Love's Labour's Lost. In the absence of the courtiers' birth parents, Nature and Time work together to teach their young charges. The lessons? Number One: timing matters. Number Two: there are things brought on by Time – like procreation and death – that no oath can control. The women know this, the men are learning it.
The Princess's request for a year apart echoes Berowne's earlier argument for seasonal appropriateness. The play is governed by the principle that timing is important.
Oaths, rules, and societal conventions are no defense against time.