These high-quality companies are often great buys during a sell-off.The stock market has been red-hot over the past year. The S&P 500 surged more than 25%, while the Nasdaq's value soared by about 33%. At some point, the market will take a breather. Market sell-offs are often ideal times to buy high-quality companies at great prices. NextEra Energy (NEE -1.06%) and Brookfield Infrastructure (BIP 0.23%) (BIPC -0.69%) will probably fall during the next market slump. That would be a great opportunity to scoop ...