Leon has the correct answer. It is not that hard to fry a chip with a bit of static.
Some people are lazy and get away with constantly touching the case as they are working and being careful about what parts they touch even when building on a carpet floor. Some people also like to jump out of perfectly functioning airplanes, whats your risk tolerance?
Haha..Ok well I guess I'll go to Radio Shack and pick one up. I've just always got away with putting in and replacing components without one. I put my video card in once with socks on and on a carpet. O.O Not the best of ideas, as I see now. =P
I have been modifying hi end audio components 5 figure range since the late 70's and have done about 70 PC builds....never wore a wrist strap since the 1st build and never toasted anything. never seen an electronics tech wear one either.
But as they say on TV "Don't try this at home" .... not that those of us who ignore this common safety advisory are unusually skilled or wreckless it is just that we have picked up certain habits which don't pose the same dangers that a novice might expose himself to and don't work in a static producing environment. I work on a wood table with a tile floor and I never touch a component except by the edges or housing. I don't repeatedly touch the case ... I just touch the case when I sit down....and then again if I leave the room and come back. I just find the strap too confining and avoid static simply by not putting myself in a position to generate any.
Touching it a couple times is an understatement. I hang onto the case like its my flotation device. Touch it every time before you touch any component, keep a forearm against it while you install components, etc.