My advice to any website designer would be to, above all, keep it consistent.
I prefer absolute urls. That’s just a preference. Google doesn’t care so neither do I, really. I have just gotten into the habit of using absolute urls.
What is an absolute URL? Example – “http://www.hobo-web.co.uk/search-engine-optimisation/”
What is a relative URL? Example – “/search-engine-optimisation.htm”
Relative just means relative to the document the link is on.
Move that page to another site and it won’t work.
With an absolute URL, it would work.