Recently, the fish population has been going down because of an oil spill in the ocean. To monitor the current population in a certain region, Danielle collects 84 fish, tags them, and releases them. Later, she collects 480 fish and finds that 16 of them are tagged.

One correct reason is:

We do not need to keep every financial document we receive. For tax purposes, comparing the amounts on your W2 form to those on your end of year pay stub would suffice to ensure the information is correct instead of keeping every pay stub from the year.

Some people keep a copy of bills they have paid; after a couple of years, it is safe to assume that there are no problems with your payments and you can discard those copies.

The same is true of your bank statements; after 3 to 5 years, most people throw away old statements. After that much time has passed, if no problems have arisen, it is not likely for one to arise.

If we were to keep every piece of financial information we receive, we would run out of space to keep them. We need to do an occasional purge of these records in order to decrease clutter.