For all my clients that I train in person, I always have them perform an assessment prior to determining the program and exercises best suited for them.
Why perform a fitness assessment
For example it may seem that if an individual can not squat to full depth or without proper form then I would not program squats for them. But that is not the case, for several reasons:
Number one being squatting is a natural and necessary movement pattern that people have been doing for a very long time, so not doing it means you are not having the quality of life that could be achieved otherwise.
The second reason is the problem is going to remain unless you fix all the pieces of the puzzle. It is a popular mindset nowadays that when people can not properly perform a movement they will look for an alternative or just stop doing it all together. That is just putting a band-aid on the issue instead of fixing what caused the problem in the first place.
You will absolutely not get the same results by squatting on a smith machine because you hurt your knee, versus fixing what is wrong with your knee and the movement pattern itself which will eventually allow you to squat with free weights.
So that is why I assess my clients, to see where they are failing to properly execute the movement and to figure out what exactly needs to be worked on. It is not to see what can or can not be done and then find alternatives.
The exercises in my programs are basic human movement patterns and there is no excuse to not be performing them or working towards it.