There are advantages of showing 100 conversations per page in your Gmail mailbox if you receive a lot of emails each day. Heavy Gmail users may receive something like 30 to 50 emails a day and these can quickly fill up your first page. If you are receiving a lot of emails and your mailbox is set to show the default 20 emails per page, then you will need to go to the next successive pages to view all your new emails. If you are like most people, then you are likely to check the first page only for any new messages, and any new messages in the next pages will be overlooked and missed. To prevent this, you should set your mailbox to show 100 emails per page, so that you can browse all your new messages from the top to bottom.
Step 9 – Scroll down and Save Settings.