Answer first
The most natural hair systems match your own hair, and often go slightly lighter in density than you might expect. Your consultant matches colour in daylight, including any grey, and chooses a density and wave that fit your age and the hair around the area.
Colour
Matched to the hair at the sides and back. A little grey blended in can look far more real for mature wearers.
Density
Too thick looks like a wig. Medium or light-medium density suits most adults.
Wave and hairline
A softer, slightly irregular front edge looks more natural than a sharp line.
Questions
Can I go darker?
You can, but the sides should be coloured to match.
Can density be changed later?
Yes, your next system can be ordered differently.