Retiring at 55 with $300,000 is challenging but not impossible, depending heavily on your expected living expenses and other income sources. Applying the 4% rule, $300,000 provides only $12,000 in annual income, which is significantly below what most people would consider comfortable. To make this work, you would likely need to supplement this with other income, such as Social Security (available in your 60s), part-time work, passive income sources, or a highly reduced cost of living, possibly through downsizing or moving to a low-cost area. It would be a frugal retirement with very little room for unexpected expenses.