Lazy portfolios in two wrapper versions

Empirically yes, over rolling 10 to 20 year windows. The S&P SPIVA report (Standard & Poor's Indices Versus Active) consistently shows that 80 to 90 percent of actively managed US equity funds underperform their benchmark indexes over rolling 10-year periods after fees. The lazy portfolios match or beat the benchmark indexes by minimising fund expense and avoiding the average-active-manager underperformance.

Yes, and this is the standard practice. The whole-household three-fund typically lives across a 401(k), an IRA or Roth IRA, and (sometimes) a taxable brokerage. The lazy-portfolio target weights apply to the consolidated household allocation, not to each individual account. Use the Bogleheads asset-placement framework to decide which account holds which fund.

Annual rebalancing is sufficient for most investors. Quarterly is more precise but adds transaction friction. The most common Boglehead practice: rebalance once per year on a calendar trigger plus opportunistic rebalancing when an allocation drifts more than 5 percentage points from target. Rebalance using new contributions when possible (buy more of the under-weighted asset rather than selling the over-weighted) to minimise capital-gains realisation in taxable accounts.

A target date fund is a single mutual fund that bundles a lazy-portfolio-style allocation plus an automatic age-based glide path. The investor holds one ticker. A DIY lazy portfolio is the same allocation but you hold 2 to 6 individual funds and you do the rebalancing and the glide-path adjustment yourself. Target date funds charge ~5 to 12 basis points more than the equivalent DIY. See the target date replacement page for the full comparison.

Marginally more diversified (international bonds add exposure to non-USD developed-country sovereign debt) but adds rebalancing complexity and another fund to track. Most Bogleheads stick with three-fund because the international-bond diversification benefit is small. Vanguard target date funds use four-fund construction because the additional fund is essentially free at the institutional scale; for retail DIY investors, three-fund is enough.

Three-Fund if you want simplicity. Coffeehouse if you specifically believe in the small-cap-value and REIT premiums and you have the discipline to maintain the tilts through periods (potentially years) when they underperform. The empirical record on small-cap-value over the last decade has been mixed; the 1981 to 2010 period gave a meaningful premium, the 2010 to 2020 period gave a discount. Pick based on your own conviction.