I think this requirement is pretty common. In Nevada I believe you need the receipts for the major components; axle, springs, steel and coupler. It make me laugh though because I have this visual of walking into DMV with a big ol' box of receipts.
"This one is for the hurricane hinge. And this one is for the fabric I made the curtains with. Can you believe that it has little teardrop trailers on it? This one is for the gorilla glue. Oh and this one for those little teardrop shaped salt and pepper shakers I bought. Have you ever thought about building a teardrop?"
..."Ok ma'am. Here's you title. Please take you box of receipts and leave!".
Joanne
KA wrote:
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p.s. Oh, one more thing..check out your state's requirements for licensing so you can be sure to do everything they require to get your trailer registered. My state requires copies of all receipts for parts used in the build.