Having a good grasp on your company's spending, even if it's just a one-person company, helps you make good business decisions. It lets you form a reliable budget and forecasts so you can develop competitive rates that bring in enough income to pay for all expenses (training, equipment, insurance) and pay yourself so you can keep the lifestyle you're used to. Above all, it makes tax time much easier and less costly!
The first step in controlling that spending is solid record keeping which, unfortunately, is a challenge for many independent contractors. If you're one of those people who have trouble tracking all of your receipts, have a look at this video by Steven Schlagel. He has some realistic tips that will definitely help.