The Globe and Mail reports in its Wednesday edition that for many people, one of the biggest attractions of investing in exchange-traded funds (ETFs) is their low maintenance. In a Globe special, Terry Cain writes that experts say, however, it is important to rebalance your ETF portfolio. Stan Wong at Scotia Wealth Management in Toronto says that investors should rebalance their equity and fixed-income allocations from time to time to reflect current objectives and risk tolerances. In addition to watching asset-class levels, Mr. Wong also recommends investors take a tactical approach to rebalancing ETF holdings -- especially when it comes to funds that focus on a certain sector of the market, or geographic region. "If the outlook for a particular sector or style of ETF falls out of favour, investors should act accordingly," he says. Since the U.S. election, there has been a significant rotation from perceived "safe assets" (such as defensive equities, government bonds and gold) to "risk-on" assets, or assets that tend to be bought during lower-risk markets (cyclical equities, high-yield bonds and energy and base metal commodities). He recommends ETFs focused on financials, industrials and materials.