I just met with my accountant and she told me that I should keep all the reciets for 3 years (please note I am in MD don't know how much taht varies buy state) but capitalized items (mixers and other things you get repaired if it breaks) for as long as you own it. Also she said to organize the receipts into categories to make it easier for end of year taxes....Like supplies)pans, racks, spatulas, Inventory items, office supplies, rrental and insurance fees, professional service (CPS< Lawyer etc), website fees, licenses, profesional deveoplment (classes, books, etc). shipping (or delivery charges).
I used excel spreadsheets to keep track or orders, quicken to track money, and file systems to keep receipts.
Hope that helps some. I do think it is very important to be organized. You might end up not getting all or your decductions in the end. No need to give Uncle Sam free money!