I just did an intarsia project where I did 18 or 19 leaves across the yoke of a sweater. I decided to try just leaving strands. I made up a swatch of one of the leaves to see how much yarn it took and made the green strands that long. They were around 6 feet or maybe a little more. I knew I would need more of the oatmeal color but made those strands shorter intending to make joins, which I did. I used the Russian join and it worked well but was tedious to do and made the work a bit thicker where it was done, but doesn't spoil the FO.
I haven't done scads of intarsia where I did short pieces and didn't know how long I could make them without getting a hopeless tangle. I had zero problem with them tangling. I think I could have made the oatmeal strands longer than I did, but whether I could have made them 3 times longer (what I needed) I don't know. When I joined in my second piece of oatmeal I made it quite long because now my greens were shorter so I thought I could get away with it. I ended up with 76 ends to work in. But I don't mind working in ends. Thank goodness.
Here is what my project looked like in progress and you can see the FO in "What'cha Knitting". I think it is called FO: Sweater for myself.