The decision between a Solo 401k vs SEP IRA or a SEP vs Individual 401k depends on your financial goals and business structure. Solo 401k allows for higher contributions and loans, making it a top choice for self-employed individuals. Conversely, a SEP IRA offers simplicity and is ideal for small business owners with employees. Assessing factors like tax benefits, contribution limits, and plan flexibility can help you make an informed choice. By understanding the unique advantages of each, you can select the retirement plan that best supports your savings strategy and ensures long-term financial security.