Skills (like Repairs or Camo) will be incrementally beneficial while you train them, but perks (like Sixth Sense or Brothers in Arms) are only beneficial once full trained to 100% mastery. Once your crew's proficiency level is trained up to 100%, you'll begin training on skills and perks. It takes 24,157 XP to train a crew from 75% to 100%. The top stats listed for a tank will only be applicable if your crew is trained to 100%. A 50% crew will be less effective at reloading, spotting, maneuvering, etc as the tank's top stats indicate (based on a formula found here). 50%, 75%, or 100% crews - what's the difference?Ī crew's training level impacts the crews performance on all responsibilities and skills trained.