How long can I keep my style up

It depends on the style you get 

~Braids 1 to 3 weeks 

~Feeding braids1 to 2 weeks 

~Classic/knotless Box braids 1 to 2 months

~Locs 1 to 2 months don't  past 10 weeks 

~Crochet style 1 month

~ Twist 1 month 

~Twist extextions 1 to 2 months 

yes and No me personally I wouldnt because I am afraid of your real hair getting matted or molding. washing your style will cause you hair to loosen and get fuzzy faster 

4 inches all over

I can braid all hair types your style my not last as long with softer hair textures