If you rely at all on SEO and organic search results to drive traffic to your store, or even if you are not reliant on SEO, but want your customers to easily find what they are looking for, then you should set up 301 redirects on your products as they are discontinued to take the customer where you’d like them to go in the event they are looking for the discontinued product – for example to the new and improved model of the item that’s been discontinued, or the next vintage of a wine.
Remember that Google knows that page address, and your customers may have it bookmarked. When you remove a page from the web, search engines need to figure out whether to keep the old page, or replace it with the one found at the new location. It’s a better experience all around if, when you remove that page from the web, you redirect Google and your customers to whatever they should be looking at in that page’s stead, instead of allowing them to simply land on a dead page and think that you left the web entirely.
In the Nexternal Order Management System (OMS), it’s super simple to create a 301 redirect on any product or category utilizing the "Unavailable Option" fields.
The Unavailable Option handles the scenario in which a customer in the Online Store attempts to access the product or category when it is unavailable (because of Visibility, because the product or category is Discontinued, etc.). You may choose to display the Default Message; to perform a 301 (Permanent) or 302 (Temporary) Redirect to a URL that you specify; or to display a Custom Message.
The principal difference between 301 and 302 Redirects lies in how they are handled by search engines. A 301 Redirect tells search engines to index the new page because it is a permanent move; while a 302 Redirect tells them to continue indexing the old page, as it is a temporary redirect and the original page is expected to return. They are identical from a customer's perspective.
On the second page of each product, shown below, (and on the product import), as well as on the first page of each Category (and the category import), you have the ability to create a 301 redirect for that page at any time. Simply select 301 redirect as shown below, and enter the URL of the page where you want folks to land when they try to get to the discontinued page. (If you desire a 302 redirect, simply select 302 instead of 301 from the pulldown.)
Once you make your selection and fill in the forwarding URL, click finish at the bottom of the page and you are all set.