Making patterns bigger/smaller

I got this from an email group that I am part of and thought that it would be great to share with all of you. I hope that you find it helpful.

One easy, no math, fool-proof way to start your foundation for any
pattern is to:
1. Chain to the width that you want.
2. Place a safety pin in the last chain stitch made.
3. Using a second skein or the other end of the same
skein of yarn, join yarn in the first stitch of the
foundation chain and work the first row of the
pattern.
4. Work the pattern until your piece is as wide as you
want it to be.(*Be sure to end with a complete
pattern repeat as called for in your directions.)
Now, for the safety pin. If you find you have chain stitches you
don't need, then simply take out the pin and pull out the extra chain
stitches until you get to your last stitch worked in the first row
and fasten off the chain stitches. On the other hand, if you need
more foundation stitches, just insert your hook and make as many as
you need before fastening off.
This is especially useful when you are chaining 200-300 stitches for
afghans. This works for me.

*Please, since I do not know how to design, I hope those who do will
help me make this clearer to the members. It really does work.