It's always nice to have extra bars. Here are a few reasons why you may want to have some hanging around, because it would leave a gap at the top of your hive. Each hive comes with 30 bars (at least 2 more than you need).

• Buy our top bar plans and add on these to save yourself some time.
• When harvesting honey, you can take your time with the bar and/or sell it right on the bar.
• When preparing a split/nuc, you can use your own brood, honey, and empty comb to start them off. 
• Since the bars are 19" long, they can be put into Langstroth hives. This means you can sell or give bars to other local beekeepers to help them in a time of need. 
• You may want to build your own nuc or bait hive.