Wikipedia:Why you should watch redirects
 | This is an essay. It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints. |
 | This page in a nutshell: If a certain page, such as a redirect, should not be being edited, that is even more reason to pay attention to it. |
The essay Wikipedia:Don't overload your watchlist! provides a list of articles which are not recommended to watch. Most specifically, it is discouraged to watch redirects, categories, templates, and closed deletion discussions. The argument made here is that these pages are rarely if ever edited after their creation, and therefore there is no need to watch them. Said essay then goes on to make the argument that a busy watchlist may be overwhelming.
This argument is of course, perfectly non-contradictory.[sarcasm]
It should rather follow that if a page should not be being edited, then that is all the more reason to keep it on one's watchlist. If someone is editing it, then that's something unusual and so something may be up. It could be a template being tweaked, it could be a redirect target being changed, or it could be a deletion discussion closure that was performed out-of-process being reversed. Or it could be any one of these being nominated for deletion at WP:TfD, WP:RfD, WP:CfD, or WP:MfD. These are all things you might not care about, if they're legitimate good faith edits.
Even so, it is because these pages are not often watched, and not often edited, that you actually should watch them. Because they're not often edited, they aren't likely to facilitate an overcrowded feed. Because there (probably) isn't much investment in their creation, you shouldn't be too bothered if someone changes them, so long as a retarget is appropriate. Hopefully, nothing happens to them, and they simply never make a blip on the watchlist and lie forgotten to do their important job of existing. But if someone does make a questionable or malicious edit to them, by inserting inappropriate content into a template (affecting all pages that transclude that template) or retargeting a redirect to an inappropriate location, then odds are it will be a bit of time before anyone notices, since no one watches these pages, because they are almost never edited.[note 1] Or, in the case of a redirect, if someone writes an article in its place, then you can see and evaluate it straightaway and then do something about it if need be.
In short, if anyone does edit pages such as these that by design shouldn't be being edited very often, you may want to be the one watching. And hopefully, by reverting any inappropriate change immediately, save someone else the trouble of having to revert it several hours or a day later.