I know i should know.
But when the pattern tell u to knit to a certain lenght. When measuring do i stretch it out flat and measure or just meausre it as it hangs ???
Panicing about my first project the front being longer than the back
Thanks for all the help guys. 
Huh. I never thought that much about it, I guess. I just lay it down on a flat surface, still attached to the needle, and measure it that way. Maybe I’m doing it wrong…
It can depend on the fiber and the size of the item. A cotton sweater is heavy and oft times will grow from the weight. I tend to measure such items hanging. But if acrylic or blend, you’re usually apt to measure on the flat.
If you’re doing pieces of a garment, best you rely on the no of rows as that’ll guarantee same length as your knitting gauge may change (bit looser, tighter on some days). If I’m not working the body in the round, I usually work all body pieces at the same time on a circ so my incs, decs, lengths all match.
cam
I rely on the number of rows, too. This is directly related to the very sound advise to check your guage before knitting the selected pattern. I hate it when a pattern tells you to knit until something is “X” inches, and it usually shows up when I’ve got two of something that need to match. I ALWAYS keep track of the rows, use the guage count and make notes. Mary