Investment in New Ventures and Economic Success Today Act of 2017 or the INVEST Act of 2017 This bill amends the Internal Revenue Code to modify various tax deductions, accounting methods, expensing rules, and cost recovery rules that apply to businesses. The bill replaces several existing provisions relating to deductions for start-up and organizational business expenses with a consolidated deduction. The new provision applies to all business types, increases the dollar limitations for expenses that may be deducted, and reduces the amortization period for costs that exceed the expensing limit. With respect to accounting methods, the bill modifies the requirements for using the cash accounting method, inventory accounting rules for small businesses, and accounting rules that apply to certain construction contracts. The bill modifies the expensing and cost recovery rules to: increase the dollar limitation for the expensing of certain depreciable business assets, modify the rules that apply to the expensing of costs related to real property, make permanent the rule that allows businesses to elect to expense 50% of the cost of certain property and recover the remaining cost under the current depreciation rules, modify the depreciation rules for farm machinery and equipment, require the Department of the Treasury to update the schedule of class lives for depreciable property, modify the depreciation rules for luxury automobiles, modify the depreciation rules for computer or peripheral equipment used for personal purposes, and reduce the amortization period for intangible property acquired by a business.