I spend my time gathering information on the different types with their individual pros and cons.
The basic foundation coverages are divided into these 4 parts:
1) Sheer
For good skin people. Likely teenagers or young skin about 10%
coverage
2) Light
Helps covers uneven shades on skin but not scars and
freckles about 15% coverage
3) Medium
Covers freckles, pimple marks and discolouration on skin
about 20% coverage
4) Heavy
Covers scars and birthmarks about 35% coverage.
So which coverage is for you? I usually use medium to heavy, due to my age and the toils of life.