When you need a redirect and when you don't

I deleted a page. Do I need a redirect?

Only if there's a sensible place to send people. Google lists "you removed a page and you want to send users to a new page" as one of the times redirects help.¹ The key word is "new page" that covers the same ground.

If there's no such page, an error is the honest answer. A "404 Not Found" tells the visitor the page isn't there. It doesn't say whether that's temporary or permanent.² When a page is gone for good, MDN says servers should send "410 Gone" instead.² That status means the page is no longer available and that this is likely to be permanent.³ If you don't know whether it's permanent, MDN says a 404 should be used.³

Google says it doesn't index addresses that return a 4xx status code, and removes already-indexed ones from its index.⁴ So an error page on a deleted page is a normal, clean outcome.

Why not send every deleted page to the home page?

It's tempting, because it avoids error pages. Google advises against it. Its move guide says not to redirect many old addresses to one irrelevant destination, such as a new site's home page. That can confuse users, and it might be treated as a soft 404 error.⁵

A soft 404 is a page that looks like an error to a reader but doesn't send an error code. Google's notes describe it as content that suggests an error, such as an empty page or an error message, which Search Console will flag.⁴

There's one exception in the same guide. If you've merged content from several old pages into one new page, you can redirect the old addresses to that merged page.⁵

I renamed a page. Do I need a redirect?

Yes, in most cases. A rename changes the address, and anything pointing to the old one now leads nowhere. MDN names pages "moved or deleted without redirection" among the common causes of 404 errors.²

You can fix the links on your own site, but not the ones elsewhere. MDN notes you have no control over the addresses used by external resources.⁶ A redirect from old to new keeps those links working. For the rule itself, there's a page on setting one up.

What if I only fixed a typo in the address?

It's still a change of address, even if it's one letter. A page at the old spelling is now a different address from the page at the new one.

So ask who has the old spelling. If you've just published the page and shared it nowhere, a redirect isn't doing much. If the page has been live for a while, people may have linked to it, bookmarked it or shared it. In that case, redirect the old spelling to the corrected one.

Which addresses should lead to the same page?

Google describes people reaching a site through several different addresses, and recommends picking one as the preferred (canonical) address, then using redirects to send the others there.¹ The old links on your own pages are a separate matter. MDN says to try to avoid internal redirects, and that if you can avoid one by correcting an internal link, you should fix that link instead.⁶

Moving a whole site is its own job. When you merge two sites, Google lists redirects as the way to make sure links to outdated addresses land on the correct pages.¹ Once you know you need one, the page on permanent and temporary types helps you pick.¹