
It is very important to understand that the trailer is not a car. It should be perceived not as a car, but as an apartment or cottage. The trailer has no engine or gearbox. But there is gas equipment, plumbing, electrical wiring, furniture and other attributes of residential premises.
Unlike an apartment, however, all of this moves from place to place and must therefore be lightweight and durable.
The service life of the trailer is very long, up to 30-40 years. Every owner customizes a trailer to suit their own needs, just as you would customize an apartment. After buying an apartment, you furnish it with favorite possessions, hang family photographs on the walls, lay down a favorite rug, and so on; trailer owners do much the same. They get used to the trailer as if it were their home, and in fact it is their home. That is why not every owner of a good trailer wants to sell it. There are very few offers for the sale of fresh used trailers, but if they are, they should be treated very carefully.
A good fresh used trailer is almost always sold for 3 reasons:
1. The owner needs money.
2. It was involved in an accident and developed irreparable faults.
3. The trailer was flooded with water or damaged by any natural phenomena.
If this is the first case, then you are lucky, but this is extremely rare.
Otherwise, you are simply wasting your money.
Example.
During the transportation of the used trailer from Germany to Russia, external wall panels began to fall off. After examining it, we understood what was going on. The trailer was in an accident. It had been struck from behind. The main frame bent. It was done, but the bent frame cannot be fixed. Externally and internally, it is absolutely normal, but with prolonged driving the frame led. The chassis geometry was distorted, and the wall panels began to detach.

Another example.
The trailer has gas equipment and gas wiring. In the case of an accident, when hitting a certain place, the wiring can be broken and there will be a very difficult to eliminate malfunction in the form of a violation of the tightness of gas equipment. Such a trailer is easier to repair and sell quickly than it is long and tedious to look for a place where gas is leaking.
Here's an example.
If you fill the floor with water and leave it in this state for a while, then after cleaning the water, mold may develop, which is very difficult to get rid of. Treatment of the floor with special chemistry saves only for a while and after a while the mold will eventually return. This trailer is also trying to sell as soon as possible.
In general, the advice is that if you want a good trailer that will last you a very long time, it is better to buy a new one and not mess with used ones.