Customized to your feet and what you need to realign your whole body structure.
For example I have flat feet and one of my hips is taller than other so the orthotics would in theory correct both and provide the proper alignment to your spine
I run through 2-3 tennis shoes per year for work. Once my knees start hurting, ankles a tad bit and back hurt more than normal I know it’s time to get new shoes. Almost instant relief. Customer orthotics in theory would correct everything even more so and provide long term benefits to just your regular insoles.
As I understand yes, they come in and out of your shoes