If there were to be a standardized approach to providing aging-in-place solutions, that would mean that all homes were built alike and that all human needs were the same, regardless of their age or ability. While universal design strategies do approach solutions in this way (irrespective of someone's age or ability), there still needs to be an assessment of what exists already, what needs to be created, and what the budget and priorities are.
Even when people are facing mobility issues, theses can be quite diverse and require many different types of solutions. Some people might be facing joint issues and require cabinets and drawers with pulls and handles that allow them to be grasped easily and opened without a lot of effort. They might need faucets and appliances that operate easily also. While universal design concepts would take such issues into account by suggesting the installation of devices that would accommodate people with joint issues, that may not be the most compelling need in the home.
Mobility issues may take the form of walking, stepping, climbing stairs, sitting, knelling, squatting, lifting, or standing. Certainly, flooring choices, the elimination of steps (including door thresholds and transitions between two types of flooring) wherever possible, countertop heights, window locations and types, and the location and choice of lighting switches and controls will have a bearing on how people with such issues function in their home. Again, some of these concerns are going to be a higher priority than others and not all are going to apply because some may already exist or not be practical to include because of budgetary reasons. Some won't be required because these types of mobility issues are not present.
Other types of mobility concerns might be reaching higher shelves or a limited range of motion that affects how far someone can extend their arms to retrieve something from a shelf, cabinet, closet, or other place of storage.
There might be sensory issues present that affect how well someone can see or hear, and the amount of lighting present, ambient noise, and alternate signals for alarms, doorbells, or appliances might be needed.
Some homes are going to need bathrooms reconfigured to allow easier access or to permit caregivers or other family members to assist with bathing, dressing, or toileting activities. Some will just need to provide more space for someone using the bathroom normally. Showers may need to be enlarged. Assist bars for safety or convenience may need to be added, but the size, style, and location of them will be matters or personal preference rather than a uniform design.
Kitchens frequently need to be upgraded, modernized, or enlarged. Cabinetry, lighting, appliances, and flooring may be high priority items. There might need to be more countertop space or storage provided - possibly areas to sit in the kitchen also.
There are so many potential solutions that be called for to meet the needs of someone aging-in-place - from those with specific physical needs to just providing greater safety in the home. Not everyone has the same requirements or budget, and not all homes are equipped the same right now or in the same condition.