A succession plan provides certainty to all people involved in a business about how a transition to new leadership will occur over time, together with the milestones that are important to ensure the transition occurs. My advice is that you get a professional who is experienced in strategic planning to write and implement the plan because of its criticality.
Training and development of staff is also a core component of a succession plan. It is understandable from a financial perspective to scale back on some overheads, but training and development of your people is an investment rather than a cost. Having the best and most competent staff is crucial to your delivery of value.
Other "costs" which are really investments are those that increase customer satisfaction and/or visits. Marketing and any costs associated with enhancing the customer experience come to mind here.
The advent of technological change and leveraging it is a good example of "change presenting an opportunity". So it makes sense to keep in touch with technology change and understand how it might future-proof your business.
The key is developing your long-term strategic plan first and then working proactively on ensuring that your business is geared towards managing change and is robust in critical areas. These can include risk management, business continuity, change management and strategic marketing (among others). So it is important to think ahead and structure your business to cope with the current environment and what is about to come - investment here can make not only longevity likely, but success too.