I recommend you save all, or almost all, your email messages forever. You never know when you might need to find something again. This subject really hit home this week when a Plus Edition newsletter subscriber asked about back issues of the weekly newsletters I send by email. Those weekly edition newsletters are also kept online at http://www.eogn.com/wp/ for three weeks and then are deleted.
My correspondent admitted he had received the email newsletters every week, but he hadn't saved them and also had not read all of them. Now that he had some time available, he wanted to go back and read what he had missed.
I must admit that I was a bit surprised because all my email messages are automatically saved for years. I assumed–erroneously–that everyone else does the same. If he used a similar process to what I use, he would never need to make this request. Every issue of the Plus Edition newsletter would have been available forever in his archived email messages.
While I am concerned first about Plus Edition newsletters, the same is true for dozens of other topics: receipts for online payment of bills, messages from cousins and other family members about the family tree, insurance documents, news of upcoming events, and a lot more should all be saved. Luckily, this is easy to do these days at no cost. In fact, some email services do this automatically without your asking.
I use Gmail, and it automatically saves everything for years. I never told Gmail to do anything special, but it has automatically saved (almost) all my email messages (including the Plus Edition newsletters) since 2004. I can go back and read any of them at any time, even years later. I wrote "almost" because Gmail does not save spam mail for more than 30 days.
Having years of email messages archived can be handy for many purposes. For instance, I recently had to supply a copy of my motorhome insurance policy before placing the camper in storage for a few months. I didn't have a copy of the insurance document with me, however. While standing in the storage facility's office, I used my iPhone to retrieve the attached file from the insurance company's email message that I received months earlier and then forwarded that message, complete with attached file, to the storage facility's office email address. Total time required? A minute or two.
I am not sure how I would have done that if my email messages were not all archived.
Gmail automatically saves all email messages more or less forever, unless you tell it not to. I should mention that Gmail does delete all spam messages after 30 days. I can also manually delete messages so that they are not archived. For instance, when a local furniture store sends me their weekly ads, I typically click on DELETE instead of on ARCHIVE. Most messages are ARCHIVED, however.
As a result, I can say that I save about 90% of all my email messages. Gmail presently saves up to 15 gigabytes of messages. That is enough space to store tens of thousands of typical email messages. I have been saving 90% of my email messages since I started archiving them on July 20, 2004. By using Gmail's excellent search methods, I normally can retrieve any specific message within a minute or two.
I suggest you do the same, either on Gmail or on any other email service that will automatically archive messages you wish to save. Aren't your email messages worth saving?
As much as I like Gmail and I have always found it to be very reliable, I also keep backup copies. I never, ever place all my eggs in one basket and will not store all my email messages in only one place. Gmail makes their own backups, but I also want my own copies. While everything is saved and is easily available online at mail.google.com, I also use CloudPull, a $14.99 Macintosh program that is available in the MacApp Store. CloudPull seamlessly backs up your Google account to your Mac. It backs up Gmail, Google Contacts, Google Calendar, and Google Drive. By default, the app backs up your account every hour and maintains old point-in-time snapshots of your account for 90 days. After 90 days, all messages are saved as normal email messages and the final versions of documents in Google Drive are saved forever. I have been using CloudPull for several years and all my email messages are saved in my hard drive as well as online on mail.google.com. When I later moved to a new Mac with a larger hard drive, all my saved messages were automatically copied to the new system.
Of course, I also save all data on my hard drive to Amazon Glacier's backup service in the cloud. As a result, I have backups to my backups.
You can learn more about CloudPull at https://itunes.apple.com/us/app/cloudpull/id404445477?mt=12.
You can find a number of other methods of making backup copies on Windows or Macintosh of your Gmail messages and storing them either on your own hard drive or in the cloud. There are many articles that describe making Gmail backups if you start at https://www.google.com/#q=backup+Gmail+messages+on+your+hard+drive.
Here is a note for present Gmail users:
There is a simple URL you can visit to get to the last page of all of your messages. This will show you the first message you ever got in Gmail, and when you signed up for Gmail. Simply visit: https://mail.google.com/mail/#search//p99999