I busted out my mad Internet research skills, and here's what I found out:
- Normally, the top and sides of the head are the focus of your stylist in a partial foil.
- Partial foils are sometimes meant to be "touch ups" between regular highlighting sessions.
- Partial foils last 4 to 6 weeks, depending on how dark your roots are.
- Partial foils are cheaper (though not cheap!), and are ideal if you regularly wear your hair down.
- This technique highlights the entire head, down to the nape of the neck.
- Full foils are preferable if you wear your head up most of the time.
- Full foil highlights can last 3 to 6 months, depending on your roots and frequency of shampooing.
- Full foils usually cost more than partials.