The saying "hope for the best, but plan for the worst" is apt when considering the unfortunate possibility of not being present for the transition of your business.
It's important in a business transition to identify those relationships, and skillsets, which you uniquely hold, and transfer those to your succession team as soon as you can to minimize the possibility that the succession team might be left without those "assets" of the business, or perhaps struggle to transfer that value to the business's new owners.