Over time, all kinds of documents, contracts, invoices and other papers that you need or want to keep accumulate at home. A spring clean will help to prevent all that messy paperwork descending into chaos. “Sometimes you don’t even know what you have anymore,” says Petra Hermann, an organizational consultant based in Germany who specializes in business and private offices. Her advice is to generally scan documents and store them digitally on a laptop, an external storage disc or in the cloud. Only keep what you really still need as an analogue document in paper form, such as your rental agreem…