The length of a column for an event depends on several factors such as the type of event, the venue, and the overall design concept. For instance, if you're planning a wedding, you might want taller columns to create a grand and elegant atmosphere. These could range from 8 to 10 feet in height. On the other hand, for a corporate event, you might want shorter columns for a more professional and sleek look, which could range from 6 to 8 feet. However, it's important to consider the ceiling height of the venue and the overall design aesthetic when deciding on the length of the columns. Always ensure that the size of the columns is proportionate to the space and complements the event's theme and decor.