We've had 1 pop-up and 3 TT's now. All were purchased new. When we traded the old, they were in about as good condition as they could possibly be in, and clean as a surgery room too! I figure, we bought them that way, when we traded them, they were leaving that way too.
Kind of like buying a new car opposed to a used one. I purchased used cars for years and years, and within a short while, the repair bills would start. Buying new meant getting the warranty, and an assurance that for 2 or 3 years there would be no costly repair bills, and ever since, we've been purchasing new cars and trucks too.
When we changed from a pop-up to TT we considered used. But we didn't like what we saw (and that years ago). Campers were aged, worn out, and just looked old and tired. They came with no warranties, and an uncertainty how long it would be before a repair was needed. (much like a used car).
Buying new, we knew what we were getting (at least we though we were). Every event that happened to the trailers is something we did, and we know the complete history of the trailer. No guessing, no surprises either.
If purchasing new, you're covered 100% for at least the first year. If any issues are going to be unearthed, it will happen usually in the 2nd or 3rd trip. These can be fixed, and once fixed, they are usually good to go for the rest of the life of the camper.
Plus, new is clean. Never been slept in before, cooked in, or the bathroom used. There's something exciting about brand new that you just don't experience with buying used.
But for us, buying new gives us the total history of the camper! Everything. And after using it a few times, learn where the vulnerabilities are and then keep an eye on them.
I cleaned enough of other people's dirt, ash and trash in my lifetime and go not rewards for doing so. I've rebuilt, repaired, and cleaned, someone else's original property and quite frankly, am really tired of doing that.
You reach a point in your life where you want something you don't have work your fingers to the bone to make it nice and usable. That's when you decide to buy something new!