I keep all receipts until I do finances next, which is usually every Tuesday. At that point:
~ I compare all of the receipts to my bank download and recycle anything that is a single category that I am not tracking (see below for details), such as regular grocery store purchases with ONLY food items (95% of ours);
~ I save the multi category receipts until the end and I break them up in Quicken, then recycle the receipt unless something else below applies;
~ I keep big purchases, warranty related, auto related, HSA related, electronics, home repairs, and any projects I wish to track;
~ Big ticket items go into a file in the filing cabinet (hanging folder is "receipts"; colored folder is "durable goods"), electronics and home repairs, too (same hanging folder; colored folders are labeled "electronics" and "house");
~ Warranty receipts get stapled to the warranty info and go into our "product info" expanding accordion file in the closet...we go through this once a year and purge the items no longer under warranty and/or what we don't own any longer...I give these with the items when I give/sell the item to friends/family (not charity, though);
~ Auto-related receipts sit in a pile for a few weeks (in the tray with our regular incoming finances/paperwork) and eventually I enter the data I am tracking into my Excel spreadsheet and then I recycle the receipt, except the car repairs; I file car repair receipts in "auto" and once a year or so, I handwrite the info into the vehicle maintenance book in each vehicle and recycle those receipts;
~ Any project-related receipts get clipped together for the month (kept in finance tray) and then I deal with those; some I keep for whatever reason, but most are then recycled;
~ HSA-related receipts are filed with taxes for the end of the year...if we have any other tax-related receipts, they also go here (car registration, for example is in taxes NOT auto because we itemize and can deduct part of the bill).