Even a wise person will make a mistake after a thousand considerations.
Tips
culture
智者千虑，必有一失 is a well-known proverb traceable to the Spring and Autumn period text 《晏子春秋》 and famously quoted in 《史记》, reminding that even the wisest can err.
grammar
者 is a classical suffix meaning 'one who...' - 智者 (wise one), 学者 (scholar), 读者 (reader). Productive in formal/written Chinese.
