First off, what is kerning?

In typography, kerning is the word for the amount of space between each of your letters. Kerning is an important device to help your copy remain legible and can even add more personality to the fonts. 

When should I worry about it?

With proper kerning, your fonts should look and feel effortless: they are easy to read, evoke your brand’s personality, and logistically make sense (SCRIPT FONTS SHOULD NOT HAVE SPACES BETWEEN THE LETTERS!) With poor kerning, your fonts can look awkward, your copy can be difficult to read, and your overall design can look disshevelled and very DIY, which can break trust between you and your viewer. It’s like trying to buy a sweater and realizing the stitches are all out of sync.

What does good kerning look like?

For most serif and sans serif fonts, you should use the standard suggested kerning that is the automatically set option in most soft wares. Only when you notice that the fonts are hard to read and you need to fix it, or if specifically directed by your designer should you mess with the spacing of the letters.

Kerning for Script Fonts

A very common mistake I see in design is adding space between letters in script fonts. In no circumstance should you add space between letters to where the letters of a script font are not touching at all. Similarly, you should never make the script font so tight that the letters are overlapping on one another.

The spacing of the letters should allow the end of each letter to connect with the following letter just as if you were writing in cursive in one fluid motion with a pen in real life.

As an added note, never use all caps when using a script font.