1. It's legally required.
2. Bookkeeping records are an excellent business management tool.
Of course, staying out of jail is a good thing. And a good basic accounting system will provide useful financial information that will enable you to run your business proactively rather than reactively when it comes to important financial decisions.
While many businesses still operate using a manual (checkbook and receipts) bookkeeping system, it's generally not a good idea to use this type of system. It's far more efficient to go with an automated system, and there are now many bookkeeping software packages on the market that won't break your wallet.
Financially complex businesses, such as a manufacturing concern, can buy industry-specific software, but there also are many generic programs available that would suffice for most businesses.
A good accounting system meets three criteria. First, it's accurate; the numbers must be right. Automation will help ensure accuracy, but it won't guarantee it. Bookkeeping numbers should be checked and rechecked to maintain accuracy.
Second, it's relevant. The system provides information that's required and needed. The law requires that certain pieces of financial information be tracked for tax-reporting purposes. Obviously, these items (which comprise a basic income statement and balance sheet) must be measured and tracked. However, it's equally important to include information that you'll need to run your business successfully.
Third, a good accounting system is user-friendly. It shouldn't require a CPA to operate and interpret. Most of the Windows-based bookkeeping software packages on the market today are pretty user-friendly. They include tutorials and help screens that walk you through the programs. Find one with which you are comfortable, even if it doesn't have some of the bells and whistles of more complicated programs.