Good point from Juliasb -- sometimes the designs are deliberately printed with a "drift". Be prepared to adjust/fussy cut around that.
Sometimes when we cut our strips we see repeats in the design that weren't so apparent with the full field... sometimes that works in our favor and other times we are rather disappointed.
I like working with stripes, and I was recently putting a border on a quilt using width-wise strips to follow the way the stripes on the pattern were designed. When you were standing back, it looked like you had repeating rows every other row or so, but it turned out each were slightly different, so it really was an 11" or so repeat. Good thing I had plenty of fabric!
I am disappointed when striped fabrics are designed with less than 4 complete units across, and have learned to carefully look at and count wide repeats (whether striped or otherwise like animal units or bouquets or whatever) will give me the completed units I want with seam allowances included.