This is a great question that I love to answer - talent management and succession planning is not only appropriate for companies of ALL shapes and sizes, if anything it is MORE important in a small company. Why is this? Well, in a small company, one employee may wear many "hats" and so if you lose that employee, you have often lost many competencies all at once. Each employee in a small company is so valuable and there is no room for low performance. It is even more important in a small company to retain knowledge, to retain procedures, to retain client data, etc. if an employee decides to leave an organization.
Family run businesses, which are sometimes smaller organizations, need to clearly use formal and objective succession planning tools, to reduce the emotional that everyone experiences in succession planning, but which is even more of an issue in family succession planning.
Every organization, whether profit or non-profit, whether government or non-government, whether private or public, whether global or domestic, whether large or small - should have a talent benchstrength-succession strategy, because this is your risk management plan for your people who are your most important asset.
Think of it this way - should only large companies have data security risk management strategies and tools? Of course not - companies of all sizes must back up their system data and have data security in place. In the same way, all companies of any size should have talent "back up" plans and talent retention and development plans in place, as well as knowledge retention plans, to reduce talent risks.
Succession planning in a small company looks different than succession planning in a large company. For example, a large organization has obviously a large pool of internal talent to draw from for potential successor candidates. In a small company, succession planning may include actions to cross-train employees on each other's jobs, so that one employee can help cover the other employee's responsibilities in the event of a job vacancy.
But again, companies of all shapes and sizes should have an effective and active succession plan in place.