From a health point of view, the fat content should be less than 20% for men and less than 25% for women. I would estimate that as a lump sum for everyone up to 50 years.
If you want to cut a really good figure in front of the mirror, you should orientate yourself as a man towards 10%, as a woman between 15 and 20%.
The health benefits are immense in terms of metabolism, hormone balance and the musculoskeletal system.
For an athletic look, a low fat content is essential and more important than the muscle content.
Note: Less muscle with little fat always looks better than a lot of muscle with a lot of fat.
Back / mobility / balance to sitting activity
A sedentary job for hours does not cause problems, but over the years it does. Back pain, shortened muscles and the associated restrictions in mobility are thus virtually pre-programmed.
The important thing now is to get moving. So-called 'Functional Training' as a fashionable term in recent years has achieved great results, but it takes time to achieve.
Note: Shortened muscles and relieving postures are not something you get overnight, it is a process over many years. The good news is that it will not take that long to fix the problems.
Shaping / muscle building / beach figure
You want to look really good physically?
That's no problem at all, the formula is:
Low fat + trained muscles = beach figure.
The trained muscles are the light part, the low fat part the more demanding part. Nutrition, i.e. moderation/abstention from eating, plays the greater role here.
Note: You can be highly motivated to train your muscles six times a week in the gym; if you don't pay attention to your diet, the beach figure will remain a dream.
Condition / Cardio / Endurance
A lack of physical condition is noticeable in everyday life when climbing stairs, moving house, romping around with children and many other occasions. Of course, a lack of exercise is the main reason for poor physical condition. A high fat content does the rest.
Not everyone wants to run a marathon. For most of them it is about getting back to the normal level you had as a child, when you were jumping around in nature all day long.
Note: A fitness training does not have to be running, there are many ways to train the heart, also with weights.