I have had Gmail accounts for many years and Google encouraged us to just save all the messages. Unfortunately, some of us are now at the limit and must delete messages. Deleting messages in Gmail is difficult when they span over a decade, until now.
Actually there is an add-on that has been out for a while called SENDER FREQUENCY. It looks through your folder and liusts the number of messages from the same sender. If you use this in a folder you can see who sends you the most messages and then keep of delete them, then go to the next biggest sender.
I use the ALL MAIL folder in my Thunderbird Gmail account. Google doesn’t actually create folder and sub folders when you say to. They add a flag and all the messages are really still in the intray but it looks like they are in folders.
Since Gmail messages are IMAP< I think you also have to enable EXPUNGE in settings to make them delete off the server also.
I like Gmail because they save your emails basically forever allowing 17 gigs of storage with each account until you delete them. I too have almost reached the storage limits of 1 of my accounts (used 12 of 17 gigs) since 2014. Your storage allotment also includes photos from your phone if you are using an android phone with a Google account and backup enabled (I don’t know about Apple iPhones). My storage issue was mostly the photos so I went & transferred them to my hard drive & a USB & deleted them from Google. I did delete most of my old emails too. I am back to only 2 of 17 gigs now.
I came across this tip from the Lifehacker site & bookmarked it. It helped me get rid of a lot of old emails fast.
How to mass delete emails in Gmail It’s a 1.41 second video. Didn’t know how to attach the video.
Gmail just made security changes late last year & I think the default settings do not save the emails anymore.
I thought everyone knew that. I wouldn’t have thought to make a video out of it.