Thanks for your post and insight. Very helpful.
When you say the asking price of 3 to 5 year old units is roughly two thirds of "new", would that be the MSRP price or the discounted (20%) price? And what discount can a buyer expect to negotiate from a private partys asking price?
I don't think purchasing an Airstream is different than purchasing any other RV. Maybe the amount of money involved is more than most trailers and lots less than a Prevost motorhome. Everything is relative. The most expensive Airstream has an MSRP of around $140,000. It is no bigger inside than other models that cost around $80,000. It is all in the amenities. So if the purchaser sells the $140,000 Airstream and asks $70,000; it can appear that the price is way out of line compared to a new one with lesser amenities. There are several models that include Safari, Classic, International and all have a different MSRP even though they may all be the same size, for example 30 feet long.
NADA is just a number and if it is a starting point for discussion with s seller then that might work. My preference for purchasing three cabover truck campers and one 30 foot trailer is to get on-line and see what they are selling for. This is even more important for used coaches as the price can be anywhere depending on condition, year, model, and even location. That way it is easy to begin to get an understanding for what something is going to cost or what you have is worth.
To answer your question the rule of thumb that I have found is that a standard box coach is worth about half the MSRP in about five years. A $30,000 trailer will be worth around $15,000 in five years. If the purchaser was able to negotiate that trailer for $22,000 the depreciation 'hit' is much less. Airstreams tend to hold their value better. Perhaps the best resource is to get on-line and check into their prices. There are Airstream dealers almost everywhere and on their websites are the new and pre-owned units and the price is often provided. I would start there.
As I indicated earlier on this thread I don't think Airstream is for the first time buyer (at least not new) as the first RV travel trailer is the 'learning curve' trailer. After that most folks have a much better idea of towing issues and what they want in their next trailer. If you watch any videos of Airstream owners rallys there are not a lot young folks present. Maybe they buy Airstreams and don't attend rallys. I don't know. Actually I think I do know and it has to do with the amount of money tied up in the unit; not a lack of desire for one.
A nice pre-owned Airstream about five years old will cost about what a new Northwood Arctic Fox costs. For some the new factor is more important. For others the Airstream factor is what is important. Sometimes it is an emotional decision based on what we want not necessarily what we need. Or what it costs.
Airforums has a lot of good information and a classified section for pre-owned units. Good luck.