Dave Grant discusses the three primary ways to contribute to a 401k: pre-tax contributions, Roth contributions, and after-tax contributions. He explains the benefits and tax implications of each method, emphasizing the importance of choosing the right strategy based on individual financial situations. The episode also introduces the mega backdoor Roth IRA strategy, which allows for larger contributions to a Roth IRA, and concludes with advice on tailoring retirement savings strategies to personal needs.