Hi, I'm working with a new type of php based site (new to me) that doesn't require a database and is nearly 100% dynamic via multiple api calls and file includes. It's designed to manage affiliate content from data feeds and works well but the content (hence the pages) only has a lifespan of roughly 6 months before being obsolete.

For visitor usability it's best these expired pages no longer exist to avoid confusion so I want to get some feedback on how to best control search engine indexing.

Since the pages are gone a 404 page is appropriate, but I have the following concerns.

- Will serving up a 404 on EVERY page after 6 months damage the sites quality in the eyes of search engines?
- Incoming links to product pages would all lead to 404 after 6 months, the site may gather many of them but none would benefit the site and having a lot of broken links all over the web can't be good.

I could make the 404 page descriptive and offer other options for visitors to find what they want, yes, but I want your opinion on if a redirect would be appropriate in this case because...

- Though the product pages become obsolete a new very similar product becomes available at that time, permanently redirecting to say the main category page for that product may be helpful.

- Redirecting MIGHT also help the site retain some of the incoming link value so that the site would benefit over time as all sites do from naturally occurring incoming links.

404 vs 301 vs ? What would you do with this type of site where every page becomes obsolete in 6 months?