What is an inappropriate method of determining withdrawal amounts in retirement?

Setting withdrawals based solely on personal convenience is inappropriate because it does not take into account critical factors such as longevity risk, market fluctuations, and tax implications. Retirement planning requires careful consideration of sustainability, meaning that withdrawals should be calculated to ensure that the individual's savings can support them throughout their retirement years while addressing rising living costs and potentially increasing healthcare expenses. A withdrawal strategy should ideally be based on a comprehensive plan that considers one's lifestyle, expenses, and the overall financial situation, rather than simply what is convenient at the moment.

In contrast, using a percentage of total retirement savings enables a more systematic approach to withdrawal, while taking only dividends or interest earned can potentially preserve principal, and keeping a fixed amount adjusted for inflation supports maintaining purchasing power over time.