E7: Pronoun Consistency: Be consistent with pronoun case and avoid shifts with pronouns like I, we, you, one, or others. Scroll down to “Pronoun Reference” at the following: http://grammar.ccc.commnet.edu/grammar/consistency.htm
People soon recognize that you need to plan time to get the work done, or one will never meet deadlines. (Inconsistent pronoun use)
People soon recognize that they need to plan time to get the work done, or they will never meet deadlines. (Consistent).