Take two neighbors that live in relatively identical homes - both built by the same company and finished at approximately the same time. The exteriors may or may not be the same, but the interiors are in terms of floor plan layout. There the similarity stops. The paint color will be different in each (unless the walls have never been touched since the day of move-in), the features that each may have added over the years will reflect their individual personality, the original flooring choices as well as any updates to those will distinguish the two homes, and personal decorating and furnishing choices will differentiate the two homes from each other. Plus, neither neighbor may be the original owner of the home.
If two neighbors living in essentially identical homes sharing roughly the same address can have these kinds of differences in just the physical needs and make-up of the homes themselves, think of how different their personal requirements could be.
For two neighbors (or even two adult siblings living near or far away from each other) their health history can be quite different - based on genetics, lifetime events, the incidence of disease or illness, their relative health, and many other factors.
It's not surprising that people's needs vary so much - even when they live in close proximity to each other. It would be more surprising if this wasn't the case.
Therefore, we have to create individual improvement plans for each potential client we engage. They have differing physical needs and requirements. Some are just aging normally with few other complaints or issues. Some have progressive conditions that require the input of health care professionals before deciding on a course of action and proceeding with a design solution.
Even for a similar need, the approaches can be different. For someone with a mobility issue that impacts how they can get into their home, part of the design takes into account whether they are using any type of mobility assistance or device such as a cane, crutches, walker, or wheelchair. It they are not but have difficulty with a major joint such as their hip or knee, this could result in a different type of solution.
In these instances, we might suggest a ramp, an inclined or sloped walkway or changing any steps that might be present to ones with a lower riser. Part of the suggested solution is going to depend on what the client wants and likes, what their budget is, what they think others might say about the design, what the local building department has to say about it, and how it will look when completed. This obviously varies by the home, neighborhood, physical location, and client.
No two solutions are likely to be identical because of all that goes into determining what works, what is required, and what is necessary in a given situation. There might be similarities, but replicating a specific solution from job-to-job would not be expected.