I've always thought that there are several links that should always work on a website. When a link doesn't exist, if you type it in you will likely get a 404 page. I put together a list of 5 links that should never give you a 404 page, they should always redirect you to the proper location, whether that is a redirect to your home page or to a relevant post.

I don't really know the implications or if there are any adverse effects to SEO in doing this. But I don't really care in this case. I much rather have a small group of people find what they need when they use this method. The method of course is just typing the name. We're assuming for the sake of this post that you don't have these pages in your site. They are either in the works, or don't exist. We are also conceding to the fact that some people type in where they want to go on a website, instead of just clicking on available links.

For example, some people might change the url instead of looking for a link on your page. The easiest and most common of this example is going "up" one level.

If you have a page like this one:

example.com/stuff-we-sell/for-men/accessories.html

Its easy to see how someone would delete accessories.html, press return and expect to receive a page that shows all that you sell for men. In that page, one would expect to find the link to "accessories" along with any other products, for example: shoes, pants, and sunglasses.

Based on that interaction with a site, I can usually make one of two assumptions. If it works, I assume other pages might also work in this manner, and I'll probably feel good about this site. I explore websites like this. In the other hand, if it doesn't work I begin to wonder about the rest of the site. What else have the owners neglected to fix before its broken.

Please note that Google doesn't do this and I'm sure there's something to augment this discussion from that fact alone, but they're also serving pages in the billions and they simply can't foresee all the different names or words a user might try to use in their urls. Besides, you have to use Google, so they're not concerned about someone leaving their site because these urls I'm talking about didn't work. I still wish that addresses like these would work: , google.com/vark. Why? because others work like that, if you go use the same method you'll find that "analytics" works, "mail" works, "news" works, as do tons of others. So why not make the others work, like their services, or other google stuff? I don't know and I don't care, but I really just wanted to point out that this isn't a discussion to see "what is google doing" or "what does google recommend"

Each website has at least a dozen words and keywords that should be part of the URL scheme. Its up to each webmaster/designer to anticipate these and take action. But each website, also has many pages that I think should always work.

Here's a list of these, surely it can be added to and adjusted for your particular case.

about

. If you don't have an official About page, then you should, but that's besides the point. The worse part of not having an about page is that people looking for it will get a 404. At the very least you should point the about page to go to your home page.

contact

. What do people need to do to contact you? Why make it difficult for them by searching through your site and finding the right place or method to contact you? That's silly, make a contact page and make sure that the /contact link works. If you don't want to display contact information or prefer to remain anonymous, then simply make a contact page that states so, this will save your visitor time and effort.

mission

. Why are you online? why are you in business, what is your purpose. If you don't have this, maybe you should reconsider being online at all.

your product

. If you have widgets, then your page /widgets should work and take you to something related to the widgets you sell.

help

. Sometimes people need help navigating through your website, maybe you have an application and your visitors might need to find out how to get around, find things or use your program successfully.

Others...

There are a few other addresses that should work I think, depending on what type of website, here's a list to give you ideas.
Legal. Especially if you have a business or organization's website
Main. Standard.
Shop. If you have a store, shop as well as, store, buy, market, and products should work.
FAQ. This could lead you to an about page or more information about your site if there isn't a formal "F.A.Q."

This is a work in progress, please feel free to suggest other words that you think should always work, or tell me why I'm wrong (even though I know I'm not).