I don’t know if it’s still true but Wes McKinney’s (Pandas author) rule of thumb for Pandas was “have 5 to 10 times as much as RAM as your dataset”. But he wrote this in 2017 so things may have changed.

That said, this is a 2023 comparison of Pandas and Polars memory usage.

https://pythonspeed.com/articles/polars-memory-pandas/