How do you know if a coin has liquidity?

How can one ascertain whether a particular cryptocurrency possesses adequate liquidity? Understanding liquidity is crucial for investors, as it affects both the ease of buying and selling the asset, as well as its price stability. Are there specific metrics or indicators that can be used to gauge a coin's liquidity? What factors should investors consider when evaluating the liquidity of a cryptocurrency? How does liquidity impact the overall performance and potential of a coin in the long-term?