What to do with feed urls once post slug changes?

Using Pretty Permalinks, if you change a wordpress post slug, it automagically directs to the new url – but what about the link to the feed for that post? Is it sposed to redirect as well? … and on a lesser note, trackbacks? (I dont use them I think I redirect them to the original post?)

My feed urls don’t seem to redirect, nor do feed urls for tags / categories – I did a big site cleanup and merged (and deleted) a lot of tags … and a lesser scale, categories and now, using the 404 Redirected plugin I am find lots of 404’s. It gets better ?? – the slugs, tags and categories (and some pages) have changed over the years by renaming, moving domains – Obviously, I have all kinds of redirections in my htaccess and in my 404 Redirections – I have had had my hands full, altho I have been able to create some redirections using regexes directly in my htaccess, so far I have hand-created 7000 redirections – just when I think I am done, here come some more! Yes, I do know about the Redirection Plugin – at one time it quit working – that is when I abandoned it (reportedly it is working again? for how long?) and switched to 404 Redirected – altho regexes are possible with Redirection, I am a bit leery about using both plugins at once and there doesnt seem to be a way to export the 404 Redirected data – it doesnt store its data in htaccess – not sure how it works but it does… I have done a lot of research and reading on all this but thankful for any ideas! I have put all the time in on this so far in the interest of SEO so I am interested in ideas other than mass redirecting all 404’s to the homepage. One note – I can see that a lot of these 404’s are coming from rogue scrapers so I am blocking as many as I can – but that is another job in itself …does it ever end? Thanks