Do you already have other insurance? You may or may not need BOP insurance depending on the coverages that you have. 
Don't Rely on Personal Coverages
Don't expect your personal insurance coverages, such as your homeowners insurance or car insurance, to cover your business activities. Most personal insurance policies specifically exclude losses related to a business.
For example, say you have a solo lawn mowing service as a side business. You might think your homeowners insurance coverage will cover you if you injure someone while mowing, and your auto insurance will cover you if you're in an accident while driving your mower around town. If you read the terms of your policies closely, you'll probably find that they don't cover either the time while you're mowing or the time while you're driving to or from jobs.
Check Your Business Policies
If you've already purchased business insurance, you might have all the coverage you need. BOP insurance is just a package of several types of business insurance. However, you need to understand your policies.
Many business owners buy a commercial general liability policy because customers want to see it, because it's required to lease office space, or because they understand the risks of not having liability coverage. However, they might check off the "Buy Insurance" box on their to-do list after buying liability coverage without thinking about things like theft or lost income during business interruptions.
BOP Insurance May Have Lower Premiums
Even if you already have all the business coverage you need, switching to a BOP package could lead to lower costs. Insurance companies often offer discounts for having multiple coverages through them, just like you might get a discount for buying your personal car and homeowners insurance together. Of course, you'll need to compare quotes both for price and to ensure that the coverages are identical.