utter drivel
To say that you need to beat the closing number is utter drivel.
Many of my best bets are 5 minutes before game time. If I am confident that the dog is the side to be on and that there is likely to be mug betting on the fav, I can't see the point in taking that opening line of, let's say +6.5.
Why not wait until 5 minutes before kick-off when the line is almost certain to be closing somewhere at +7.5 or even +8 ?
The only requirement for consistent winning is to place bets at better odds than the true value of those bets. The main requirement to achieve that is to have better information, or be better at analysing available information, than the majority of the betting public.
Line shopping enables you to wring out that extra 1 or 2% profit. I personally would never have just one book - for one thing, at any given moment there is a good chance that at least 1 of the 30 or so books I use will be having server downtime, site maintenance and so on.
Some books are very strong and more or less unbeatable on some sports. But on others they appear to have hired a guy fresh out of diapers to set their lines. With all the books I have, I am able to bet against a guy fresh out of school in every sport I bet on. Why would anyone want to place most of their bets aaginst a sharp guy when by opening up more accounts they can place most of their bets against a relatively clueless line setter?