number of php includes on one page?

Is there a safe number of php includes you can use in anyone web design?
Is it safe to use it for
1)header
2)navigation
3)footer
if all pages are alike?

How does using php include effect SEO if you place your text navigation in the php file?

I have finally stopped procrastinating and begun to implement this to cut down on updates on large sites. However, I really don't know much about it.

The includes are all done by the server so the generated code is XHTML still. I don't believe it effects SEO or any other aspect of your site for this reason.

Look at the source of http://www.ldstroop21.org/. That code is full of php includes, but you would never know it.

I guess it's possible to have soooooo many includes that you just freak your server out, but that would be hard to do.

You can use a ton of includes. Includes themselves won't affect SEO, but content structure may.

Thanks Guys! I was most concerned about SEO but since the include pages are "there"... it makes sense that it won't be effected.

No problem Google sees websites just as your browser does...

Summary: I just started running at the mouth, so I put this at the top because it's what you want to know.

I wouldn't go as far as Ryan, but don't worry about a couple of dozen includes. They are almost identical to having the code written right on the page.
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Aye, afaik you can have unlimited includes in the theoretical sense that you can have unlimited html. You certainly shouldn't strain your server with 100 or so. Apache collects the file in milliseconds, and the rest of the function just has to make it visible to the server in the correct format -- barely more than the Windows "paste" function.

As far as SEO, all the people I have heard interviewed swear that the spiders basically look at the rendered page just like an html page, only giving consideration to not clogging the site. This may be problematic as far as links with $_GET variables goes, . . . getting off the subject here.

SEO spiders see the site after the includes are included, and any commands inside them have run. Having an include (or a dozen or two includes) is mostly the same as having the code written on the page.

Thanks Mason.. excellent info

Yep, I agree. I can't imagine a scenario where someone would need 100 includes, though