Attachments in Gmail are marked in threaded view with a paperclip icon next to each message that has an attachment
and also in the search results as with the first message below:
However, sometimes it is not shown, as with the second message above and in the threaded view of that same conversation below:
How do you make them all show? It is very tedious to find attachments you know are there when the icon shows up in neither the search results nor the threaded view.