The used hook machines prices and used bulldozers are generally high

Not so, used excavators and bulldozers are generally cheaper than new equipment.
Typically, used excavators and bulldozers cost between 30% and 70% of the price of new equipment. As a result, prices for used equipment are generally low, which is the main reason for the high demand in the market.
For those individual users and small and medium-sized project contractors with limited funds, the price of second-hand equipment is much cheaper and more in line with the budget. This cannot deny the objective fact that second-hand equipment is cheap.

Of course, the price of second-hand equipment also depends on its age, mechanical condition, and equipment configuration. The longer the service life and the more serious the wear and tear of second-hand equipment, the price will naturally be much lower. Second-hand prices for high-end and large-scale equipment are also often higher than standard specifications.
But the general trend is that the price of second-hand equipment is generally lower than that of new equipment. On the one hand, because the value of equipment diminishes with use. On the other hand, there is a large supply in the second-hand market and the pressure of price competition is high.
In fact, the low price of second-hand equipment is one of the important reasons for the large demand. But at the same time, users also need to make a moderate trade-off between price and performance according to the mechanical condition and equipment configuration. Only second-hand equipment with a high match between price and performance can exert the highest value.
Overall, the fact that prices for used excavators and bulldozers are generally low, with significant price advantages, should not be taken lightly. However, high-priced second-hand equipment also exists, and users still need to be cautious when choosing.

The key point is to find the second-hand equipment with the best price and cost performance through understanding the mechanical condition and comprehensive evaluation, so as to give full play to its price advantage and realize the economic benefits of equipment procurement and use.
Hope the above explanation can provide you with reference. If you have any questions, welcome to ask, I am happy to provide further help