How do you measure whether an LLM or RAG project you worked on is efficient?

"I got in through a referral, and because the role was brand new I was an early applicant. The whole process ended up being about six or seven conversations across the recruiter, hiring manager, three PMs, an engineering leader, a research scientist, and a product marketing leader. What stood out was how practical it all was: they kept pulling on my real work and on their actual robotics and world-model direction instead of wasting time on random hypotheticals. The hardest parts were when the scientist went deeper technically than I expected and when I got too relaxed with the product marketing leader because she felt so casual. I finished the full loop feeling like the interviewers were engaged, grounded, and very focused on whether I could do the real job."