'Decrease 1 stitch at the neck edge on the next and every alternate row 8 times'
but they don't generally give any instructions about what method of decrease to use or where to place the decrease i.e. on the edge or a stitch or two in from the edge. They also often tell the knitted to cast off a block of stitches at the bottom of the Front neck shaping rather than putting the stitches on a stitch holder.
The picture above is an example of how many knitters will shape a round neckline when they are given a minimal amount of information in the pattern. The stitches at the centre bottom of the Front neck have been cast off and the decreases have been worked as 'knit 2 together (k2tog)' on the neck edge on both sides of the neckline. As a result the neckline has very little flexibility and the decreases on the edge of the neckline make it very difficult to pick up stitches neatly for the neckband.
In this second sample the bottom of the neckline has been cast off again but the decreases have been worked 2 stitches in from the edge. This does make the edge much easier to pick up stitches through, but in this sample the same method of decrease has been used on both sides of the neckline shaping i.e. k2tog. Looking at the sample the right hand neckline edge has a 'fully fashioned' finish. The k2tog decrease leans towards the right which is in the same direction as the edge is being decreased. As a result it gives a clear column of stitches leaning to the right - following the shape of the neckline.
The left hand side of the neckline (as you look at it) has been shaped using the same right leaning decrease i.e. k2tog. The decrease is worked 2 stitches in from the edge so the neckline edge is still smooth for picking up stitches for the neckband, but the knitted fabric does not have the same smooth line of stitches following the direction of the neckline shaping. It does not mirror the other side of the neckline. In order to mirror the neckline shaping you need to use a left leaning decrease such as 'slip 1 knit 1 pass slipped stitch over (skpo)'.
For the shaped section of the neckline (the decreases,) I have used a k2tog decrease on the right hand side (as the sample faces you) and a skpo on the left hand side. Both decreases are worked 2 stitches in from the edge. As a result the edge of the neckline is smooth making it very much easier to pick up stitches through the edge for the neckband and I personally like the 'fully fashioned' finish that is achieved by working 2 stitches in from the edge of the knitting.
The images below show a close-up of the round neckline on 2 different garments. Both garments are knitted in stocking stitch, one with a k2, p2 rib and the other with a k1, p1 rib, but both with close fitting necklines. Due to the way the neckline has been shaped it was much easier to pick up and knit a very neatly finished neckband.
These two examples show the neckline shaping on a stocking stitch garment. I would still use this method of shaping i.e. the decreases worked at least 1 or 2 stitches in from the edge, even when knitting different stitch patterns as it makes the neckline much easier to finish neatly and I like the detail it adds.
This last picture is a v-neckline but it shows how the fully fashioned decreases have been worked within a stitch pattern. There is a 2 stitch wide column of stitches either side of the neckline just inside the garter stitch neckband.
To work fully fashioned decreases to shape the Left Front neckline (the right had side when looking at the pictures) work to the last 4sts, k2tog, k2.
To work fully fashioned decreases to shape the Right Front neckline (the left hand side looking at the picture) k2, skpo, work to the end of the row.
I would also work fully fashioned shaping at the armhole edges, the sleeve cap of a set-in sleeve garment and the raglan seams on that style of garment.
I hope this 'article' gives some of you the confidence to realise you do not have to follow a pattern word for work. The pattern will tell you how many times you need to work the decreases but you can decide where exactly you are going to work those decreases i.e. 1 or 2 stitches in from the edge of the knitting and what method of decrease you want to use.