Hovering with the mouse above the upvoting arrow of a comment shows the text "this comment adds something useful to the post". Therefore arguably the number of upvotes a comment receives equals the number of people who find that "the comment adds something useful to the post", and thus a comment with no upvotes is found useless by everybody.
Is it considered good practice to remove comments of one's own after some time (say, a few days) if they have received no or only very few upvotes?
There is a related question Cleaning up comments, but that question addresses such cleanup done by the moderators.