If you don't process your mail daily it tends to become clutter, either on a side table, your desk, or another area. That's a mess and you'll probably lose something important eventually. Consider using a small basket or box to contain your daily mail until you can process it weekly. This keeps your mail handy, you don't have to worry about losing important mailed documents such as tax notifications or car registrations and it will help keep clutter to a minimum.
Personal finance weblog The Simple Dollar started recommending this system after a friend of the author nearly had his house go into a tax auction due to losing a property tax notification.
This seems like one of those tips that's so common sense we don't need to create a post, but I know in my bachelor years my mail accumulated in a clutter pile and I sometimes lost notifications. So did the author at The Simple Dollar. If you have mail clutter issues, you may want to give it a try.
Start a "Mail Basket" and Process It Weekly [The Simple Dollar]