I'd only use primes if I have enough camera bodies to hold them. Changing lenses can result in dropped lenses, bodies, and lost shots.
Keep one prime on a body, and a zoom on the other.
Perhaps a 24-70mmL on one body, and a 100L or 135mmL on the other body.
I do use primes for some theater photography where I have a 6 foot table and I can line all of them up without any danger of them dropping. Even still, I hate to change lenses frequently. I use 35mmL, 50mm, 85mm 1.8, 100mmL, and 135mmL. I bring a 16-35mmL just in case I need really wide.
I get to shoot rehearsals where no one is running around to knock my lenses off the table. I'm considering selliing them and buying a 24-70L. The 5D MK III is good enough in extreme low light to barely get by with f/2.8, and I'll keep the 100L and 135mmL.