What if the door squeaks when it opens and closes?

You can use professional lubricating oil or waxing.

When applying lubricating oil, it is necessary to prepare a hard paper shell, roll it up, then aim one end at the gap of the hinge, and then drop lubricating oil on the hard paper shell to make the lubricating oil flow into the deep gap of the hinge. After ensuring that all lubricating oil permeates in place, open and close the door leaf several times to eliminate the rust inside the lotus leaf and solve the squeaking problem.