One common mistake that people often make in their writing is using the phrase "must of the time" instead of "most of the time".

This mistake is made due to the phonetic similarity between "must" and "most". However, the correct phrase to use is "most of the time".

For example, instead of saying, "I must of the time go to bed early," the correct usage would be, "I most of the time go to bed early."

To avoid this mistake, it is important to remember that in this phrase, "most" is used as a quantifier to indicate a large amount or a majority, while "must" is used to express necessity or obligation.

Linguix grammar checker, an advanced tool, can help you identify and correct this kind of common mistake in your writing.