I normally delete the bigger attachments from e-mail (after having saved them to my hard disk). This keeps the eM Client database smaller and enables me to search those attachments with a desktop search program.
In Thunderbird I see a text in an e-mail when attachments have been deleted. It shows the date of deletion, the name of the person who has deleted the attachment, the original filename and size of the attachment.
I would like it if eM Client would also add this functionality.