Advantages to be a contractor yourself
If you yourself buy building materials, make an order of components, organize the delivery and warehouse for construction site, then your savings will be about 20-25% of the money from building a house. That in itself there is not a few, because your overhead costs will be much less, in comparison with the costs of the construction company, which, moreover, adds to the final price the percentage of its profit, and you also do not have to pay for the services of forwarders for construction.
Now you can talk about the advantages of the customer-heaning customer
The positive side will be a significant savings for the individual construction of houses. You can also note the possibility of the customer to have full control over the situation and the final result of construction.
If possible, dealing directly with subcontractors, the owner can monitor the quality of work. But this method also has its disadvantages.