I don’t think I’m painting with too broad a brush when I say: no payment-shopper got through life by doing long-division
I can easily explain why you should lease, but how takes time, and effort, and curiousity and math and determination. If you are short on any one of those, and you still want to lease and get a good (better than they likely woukd on their own in the finance office) deal, pay a professional. 
Memba Boltmania 1 and 2? e-trons, 4xe, NJ EVs a plenty, Camaros, V60s, there were so many surprise babies! 