  We explore the vacua of the $Z_3$-symmetric Next-to-Minimal Supersymmetric
Standard Model (NMSSM) and their stability by going beyond the simplistic
paradigm that works with a tree-level neutral scalar potential and adheres to
some specific flat directions in the field space. Key effects are demonstrated
by first studying the profiles of this potential under various circumstances of
physical interest via a semi-analytical approach. The results thereof are
compared to the ones obtained from a dedicated package like \veva ~which
further incorporates the thermal effects to the potential. Regions of the
phenomenological NMSSM (pNMSSM) parameter space that render the desired
symmetry breaking (DSB) vacuum absolutely stable, long- or short-lived (in
relation to the age of the Universe) under quantum/thermal tunneling are
delineated. Regions that result in color and charge breaking (CCB) minima are
also presented. It is demonstrated that light singlet scalars along with a
light LSP (lightest supersymmetric particle) having an appreciable singlino
admixture are compatible with a viable DSB vacuum and are much relevant for the
collider experiments.
