My uncle told me I was wasting money on drip edge and I should just use roofing nails and caulk
He came over when I was framing out my 8x10 and saw the drip edge I bought at Home Depot. He laughed and said I was overthinking it, that real shed builders just nail down the shingles and slap some caulk on the corners to stop leaks. I tried his way on my first shed two years ago and it leaked bad every spring, water got behind the fascia and rotted the plywood edge. This time I stuck with the drip edge and even added a little extra overhang. When he saw the finished roof he just shrugged and said it looked fine, but I know he still thinks I wasted $12. Anyone else have a relative who gives bad shed advice that you just ignore?
Your uncle sounds like the kind of guy who thinks a crescent wrench fixes everything. Caulk and roofing nails are a temporary fix that'll cost you ten times more in repairs later. Probably the same guy who says you don't need to prime before painting.
My uncle Charlie gave me the same talk about my 12x16 shed last summer. I just nodded along while I installed the drip edge anyway because I saw the same rot you did on my neighbor's roof job. Cost me less than $15 and saved me from having to replace the whole roof deck in a few years.