Why "obviously"? This is the 21st century.  ;-)

Seriously, this is one of the reasons for the archive feature. By taking older messages out to year-based archive stores, you avoid the need for the working message stores to grow indefinitely. Splitting your messages into subfolders also helps, as each subfolder is made into a separate file in the filesystem. And for new accounts, you could now consider using maildir format, where each message is a separate file.

Zenos,

Thanks for the reply. But the archive folder is also a limiting factor in my case. My files for any one year are more than 4GB. So I am in a fix here.

Regards,

LS

If yearly will be to much, make it monthly in Account settings /copies & folders / message archive (archive options)