thanks for the intro shakil!
The answer is...... depends on what you are trying to achieve and how much of a crusade you are on to get the most out of the system.
Although eventually you will get to the stage where the ads will run themselves, like any other PPC there will always be new advertisers coming in and shaking things up.
As far as time managing a campaign, it is a lot of time for the first week (usually a few hours a day, assuming that Google's interface is working OK).
We cross reference the traffic on our ad tracker and look at search strings to check for obvious words that might be better served going exact match, or might need to be submitted as a negative keyword. That will usually take a little while on a busy campaign but pays off in the long run. Rarely now do we get campaigns with less than 3% CTR, even in competitive arenas, and we don't need 100's of keywords in them because you can cover all the bases with choosing the right keywords and exact and phrase match in conjuction with negative keywords.
When you set up a campaign and Google suggest you pay £2.52 or something like that, see what impact reducing it to say 15p has. My point there is that Google's stats are so wide of the mark that they will almost always get it wrong, that's not a criticism of Google, just the way the system is, exploit it.
We added a campaign about 20 minutes ago. Google's suggestion tool indicated we might get 9.6 clicks a day for the campaign. According to the tracking tool we have already had over 10 clicks, so we can increase our daily spend rather than waiting until tomorrow when most people would start to complain about this. Obviously because the figures were so wrong we would get a decent overdelivery credit initially, but I'd rather get the campaign right straight off the bat and get that CTR as high as possible as quickly as possible, without doing R & D first.
So to answer the original question. It could take you a few minutes a day, if you were not that obsessive and didn't mind wasting your money (and that's not a criticism DrCool!), or you could invest some time early on to get the campaign spot on and then sit back and reap the rewards with say an hour or so's work on a daily basis for decent sized campaigns.