Just an experience to share.... I was doing an intarsia lizard on the front of a little sweater and there were places where I thought I could just strand (Fair Isle if you will) across to avoid too many balls. It worked but when I got the whole lizard done I was not happy with any of the parts where I had done mixed stranding and intarsia. So I never finished the sweater. I wanted to take the whole lizard out and do it over-- all intarsia with no cheating. But I've never gotten around to it. It may have just been something about the way I did it, tension or such, but I think it was a bad idea on my part.