ok how important is it? to use torque wrench

[single]

All of the above are good answers. Get one and use it. Get a good one that is accurate and calibrated. ebay is a good place to get some quality torque wrenches for a good price. Proto is one of the better torque wrenches that go cheap on ebay. I have several SnapOn, Mac and Proto torque wrenches. I can't say any one is better than the other.

[benbeaux]

Believe or not, the Harbor Fright torque wrenches are pretty good. I've cal'd about a half dozen of the 150 ft-lb 1/2" drive units & one each of the 1/4 & 3/8 drive units. All were with in the +/-4% ISO & ASME spec for wrenches. They are a chinese knock off of older model Utica wrenches from the early 90's. Other than the gritty feel, they work the same. I have one of each in the tool box since I'm a DIY person, but if I made a living at turning wrenches, I'd use Snap-On.

As far as beam type wrenches, they are accurate & you can still get them in ft-lb models, but they are a total PITA to use.

The sorriest torque wrenches I've ever worked on are the "digital" Craftsman wrenches.
Craftsman Digitork Torque Wrench, 25-250 ft. lbs., 1/2 in. Drive - Model 44597 at Sears.com

[MOREPOWER]

I use one always on larger nuts, I want a small version roo cheap.
Mines a $20 1/2 drive China made from Pepboys.