Ensure consistent formatting and proper usage of environment variables in Dockerfiles. Remove unnecessary quotes from ENV declarations and choose between ARG and ENV based on their intended scope - use ARG for build-time configuration that may change between builds, and ENV for runtime configuration that containers need during execution.

Key guidelines:

Example:

# Good - consistent formatting, appropriate usage
ARG PYTHON_VERSION=3.11
ENV PIP_CACHE_DIR=/cache/pip
ENV VIRTUAL_ENV=/app/venv
ENV TRANSFORMERS_CACHE=/app/.cache/transformers

# Avoid - unnecessary quotes and inconsistent formatting  
ENV PIP_CACHE_DIR="/cache/pip"
ENV VIRTUAL_ENV=/app/venv
ENV TRANSFORMERS_CACHE="/app/.cache/transformers"

This approach improves readability, reduces confusion about when quotes are necessary, and ensures proper separation between build-time and runtime configuration.