First of all, if you have a fixed unit, you can give these things to your company, and they will check them for you. I remember that the quality inspector, safety officer, material engineer and builder all check once every two years. Budget officer for three years. You can go to the website of the corresponding inspection agency for details. The quality inspector, materials engineer and builder go to the Liaoning Provincial Urban and Rural Construction Department for verification, the budget engineer goes to the Liaoning Provincial Cost Management Office (it seems to be the name, I can't remember clearly, I'm sorry) for verification, and an archivist goes to the Dalian Urban Construction Archives for verification (at the north gate of Dalian Railway Station, go east, there is a bank, and then go to the second floor).