zsh-abbr adds roughly 13ms + 1.65ms/abbreviation to first prompt lag, 20ms + 1.65ms/abbreviation to first command lag, and 13ms + 1.65ms/abbreviation to exit time.
Explanations of the measures are at https://github.com/romkatv/zsh-bench#what-it-measures.
Raw single-run data is available at https://oletsdev.notion.site/oletsdev/zsh-abbr-f2f3a1de08f14c8f8686ece171175400.
The performance suite uses zsh-bench. Run the performance suite with
zsh-bench --isolation docker --config-dir ./perf -- not-installed fresh-install zero-abbreviations ten-abbreviations one-hundred-abbreviations