On the matter of decluttering paper and documents, here is a quick tip on those papers that you should keep but are oh so fiddly. I am referring to receipts, especially for warranty purposes. You need to keep receipts as proof of purchase when you may need to get the item repaired within the warranty period, yet nowadays, the receipts are printed on heat sensitive paper which fades over time.
One easy way to keep track of all this is to take a snapshot of the receipt and email it to yourself. Create a new folder in your email to store all such documents. To make it easier to search, the email subject should contain the item details, name of store and the expiry date (rather than the date of purchase).
For example, Philips kettle, Harvey Norman, 3rd June 2017.
This makes it easy for you to find the right receipt without opening all your emails, and when the expiry date has passed, you can delete the email. Most stores will accept a reprinted copy of the receipt, but do check when you are purchasing the item.