Pronouns stand in for nouns. Without them, reading becomes annoying:

The band Vogon Soup has been together long enough that Vogon Soup knows Vogon Soup’s strengths.

Once readers know what the noun is, pronouns act as shorthand to refer to it. Reading a name, or any noun, again and again is tedious. And because most pronouns are shorter than the nouns they replace, they save readers — and writers — time.

The band strengths.

Pronouns are extremely useful, and most cause little or no trouble. Misusing pronouns, however, is liable to confuse or irritate readers as much as failing to use them at all. The ones that are most likely to go wrong are discussed here.