When you actually need new
The common cases for new:
DEF (diesel exhaust fluid) handling. ISO 22241 purity requirements are strict, and contamination can damage SCR systems. New or dedicated containers are the norm.
Pharmaceutical or aseptic-fill staging. Validated cleaning processes require known-history surfaces, and used bottles often don't pass receiver audits.
Some food applications with strict packaging-history requirements. Some certifiers and buyers require virgin HDPE for direct-contact storage.
UN/DOT-marked transport of regulated chemistries where the receiver's compliance team requires new containers.
If you're not in one of those categories, a used tote with known, compatible previous contents is usually the better value.