There are many advantages to work with isolated objects, isolating an object or part of a mesh, it lets you focus specifically on a certain area of the scene, this helps to analyze the scene better, it is also lighter for the viewport to compute while working on a big or heavy Blender scene file.
I have discovered that I work faster on an object and get the proportions right more easily when I work on an isolated object.
Isolating the object
To isolate the object, simply select the object and then go into the Object > Show/Hide > Hide Unselected or do the keyboard combination Shift + H
What hide unselected does is it hides everything that is not already selected, this operation only happens if you have one or more objects selected.
You can also select the objects using the Outliner, which by default is in the top left.
To undo or show all the objects, go into Object > Show/Hide > Show Hidden Objects, this will show all the objects, the keyboard combination is Alt/Option + H.
If you don’t want a specific object visible, for example if here is a mesh that is dense or heavy to compute in the viewport you can go into Object > Show/Hide > Hide selected, you can undo this process by undoing it or by choosing to go through the earlier steps of show hidden objects, the keyboard combination is H
This is a good process to include in your workflow.