well depend on you that what do you want and what is the acceptation form your website so if you want good and quality and harry up result then you will spend more time but if you have more website then can't give more time as a one...
It's gets much faster once you get into the swing of things. I have a list of 10-20 blogs and forums where I spent an average of 1 hour per day. In addition to this 1-3 hours per week on other SEO stuff. Anything more than 3 hours per day is just a waist. Outsource it!
I spent about 8hrs of my day on SEO, we're working as a group so it won't be that hard to put some link juice on our site...
well i mostly spend my 2to3 hours daily on SEO work and really it is giving me so much benefit so thing is it depends on person to person and need of your website that how much it has need of advertisement if your website need much more advertisement then you have to spend more then 3to 5 hours daily like http://www.mobile-phone.pk this link has not need so much advertisement.
SEO the basics such as placing your keywords in the title, meta description, meta keywords and spread about naturally in the content is simple enough, bu getting good backlinks is where the problem is