The US has a confusing landscape of tax-advantaged investment accounts: 401(k), 403(b), 457, traditional IRA, Roth IRA, HSA, SEP-IRA, SIMPLE IRA, Solo 401(k), 529 plan, and more. Each has different contribution limits, tax treatments, and rules. This cluster provides the navigation map.
The canonical entry point is AccountTypeStrategy, which lays out the order to fill these accounts. Everything else covers specific accounts in more detail.