How much of a boost in net returns can financial advisors add to client portfolios? According to Vanguard, maybe as much as 3%. In a recent paper from the Valley Forge, Pa.-based mutual fund and ETF giant, Vanguard says advisors can generate returns through a framework focused on five wealth management principles:

• Being an effective behavioral coach. Helping clients maintain a long-term perspective and a disciplined approach is arguably one of the most important elements of financial advice. (Potential value add: up to 1.50%.)

• Applying an asset location strategy. The allocation of assets between taxable and tax-advantaged accounts is one tool an advisor can employ that can add value each year. (Potential value add: from 0% to 0.75%.)

• Employing cost-effective investments. This component of every advisor’s tool kit is based on simple math: Gross return less costs equals net return. (Potential value add: up to 0.45%.)

• Maintaining the proper allocation through rebalancing. Over time, as its investments produce various returns, a portfolio will likely drift from its target allocation. An advisor can add value by ensuring the portfolio’s risk/return characteristics stay consistent with a client’s preferences. (Potential value add: up to 0.35%.)

• Implementing a spending strategy. As the retiree population grows, an advisor can help clients make important decisions about how to spend from their portfolios. (Potential value add: up to 0.70%.)

But Vanguard notes that while it’s possible all of these principles could add up to 3% in net returns for clients, it’s more likely to be an intermittent number than an annual one because some of the best opportunities to add value happen during extreme market lows and highs when angst or giddiness can cause investors to bail on their well-thought-out investment plans.