So much of this is gut and taste. I've essentially got about three line-heights going (loose, standard, tight) because loose leading can look truly terrible on short amounts of text, and I also tend to prefer basically no leading on text that's all uppercase or perhaps enormous titles.
Getting this stuff right is so important though and even if most of your users don't "appreciate good typography" they can definitely "feel" it if it's wrong.
So much of this is gut and taste. I've essentially got about three line-heights going (loose, standard, tight) because loose leading can look truly terrible on short amounts of text, and I also tend to prefer basically no leading on text that's all uppercase or perhaps enormous titles.
Getting this stuff right is so important though and even if most of your users don't "appreciate good typography" they can definitely "feel" it if it's wrong.