  We examine the charge density wave (CDW) properties of 1$T$-VSe$_{2}$
crystals grown by chemical vapour transport (CVT) under varying conditions.
Specifically, we find that by lowering the growth temperature ($T_{\mathrm{g}}$
$<$ 630$^{\circ}$C), there is a significant increase in both the CDW transition
temperature and the residual resistance ratio (RRR) obtained from electrical
transport measurements. Using x-ray photoelectron spectroscopy (XPS), we
correlate the observed CDW properties with stoichiometry and the nature of
defects. In addition, we have optimized a method to grow ultra-high purity
1$T$-VSe$_{2}$ crystals with a CDW transition temperature, $T_{\mathrm{CDW}}$ =
(112.7 $\pm$ 0.8) K and maximum residual resistance ratio (RRR) $\approx$ 49,
which is the highest reported thus far. This work highlights the sensitivity of
the CDW in 1$T$-VSe$_{2}$ to defects and overall stoichiometry, and the
importance of controlling the crystal growth conditions of strongly-correlated
transition metal dichalcogenides.
