How much is enough?

I am currently knitting the Newspaper Carrier bag from www.cu-needleworks.com.

I am doing the largest bag that is 25 inches long before felting. The directions for the strap are to do as long as you want…which is a problem because I have no idea how much the yarn will felt up.

Is there a general RULE of thumb as to how long I should make my strap?

Thanks,
usamacka

The only way to know for sure is to knit a swatch and felt it to see how much it shrinks.

Different yarns felt at different rates so Marilyn is correct that swatching is the best way to tell how it’ll work for you.