From 2007-2012, the auto sector had an aggregate 3.1% average annual decline in revenue due to the combination of falling disposable incomes and increasing prices. Crude oil volatility also didn't help the sector, IBISWorld says. "The automotive sector's high sensitivity to consumers' purchasing power ultimately resulted in high revenue volatility during the past five years," IBISWorld says, adding that a fiscal cliff on top of already high and volatile gas prices does not bode well for the sector over the next five years. 2. Luxury Retail Apparel Retail apparel includes women's clothing stores, shoe stores and department stores. Luxury apparel brands like Ralph Lauren ( RL), Tiffany ( TIF) and Michael Kors ( KORS) also will suffer from the repeal of tax cuts. Since 2007, the sector's revenue has dropped at an average annual rate of 2.3% because of falling disposable income and weaker demand. "By contrast, those selling essential items, like babies' and children's clothes, will be less affected because demand for these items are based more on need rather than keeping up with trends," the report says. 3. Entertainment Entertainment is a luxury, meaning "consumers are quick to cut them out of their budgets once per capita disposable income begins to decline," the report notes. Companies in that industry include museums, casino hotels like MGM Resorts ( MGM) and Caesars Entertainment ( CZR), and golf courses and country clubs. The entertainment sector's revenue has fallen at an average annual rate of 0.1% during the past five years, which "masks dramatic fluctuations over the period," the report notes. The sector's revenue was falling in 2008 even before disposable incomes dropped and a rebound in consumer spending power "has not completely revived this economic segment, which foreshadows its deep potential drop if tax breaks are not revived at the end of 2012," IBISWorld says. For small businesses, whether they're in the hardest-hit consumer-spending industries or elsewhere, it will be even more important to make smart financial and cost-savings decisions. Next year "is really going to be a time to weed out a lot of people that aren't serious about their small businesses. The cream of the crop is going to rise," says Jason Nazar, co-founder and CEO of Docstoc.com, an online resource center for small-business advice, lease agreements, incorporation documents, business plan templates and other documents. He suggests business owners "hunker down" in the first quarter to gauge how changes will affect them. "The fiscal cliff sounds much worse than it actually is," Nazar says. "Even if the deadline passes, most of the tax implications for small businesses don't happen immediately." That said, the increasing payroll tax is "a very real concern for small businesses," he says. "It immediately affects fixed expenses." -- Written by Laurie Kulikowski in New York. Follow @LKulikowski To contact Laurie Kulikowski, send an email to: Laurie.Kulikowski@thestreet.com. >To submit a news tip, email: email@example.com.