i have a dark brown straight long hair and i use blue-black permanent colour for almost 3 years(i dye all hair, not just roots), its not demaged  but every time when i dye my hair hue stays beautiful and shinny just for the firist week and than it starts to fade out with some black-grey-brownish hue without shine..what should i do?to go to sallon or change produts that i use?

i have a dark brown straight long hair and i use blue-black permanent colour for almost 3 years(i dye all hair, not just roots), its not demaged  but every time when i dye my hair hue stays beautiful and shinny just for the firist week and than it starts to fade out with some black-grey-brownish hue without shine..what should i do?to go to sallon or change produts that i use?

No worry, you just need to refresh your hair with a toner, for refreshing your hair I'd recommend Color by robert craig, it doesn't contain any ammonia or peroxide so it's very gentle with the hair (it's also permanent!).

Going to the salon, would just be a waste of time and money.

Do not use permanent haircolor with ammonia in it to refresh ends and midshafts, it'll destroy the hair in the long run.

http://www.merchantamerica.com/robertcraig/index.php?ba=view _category&category=2331

Shades natural black or jet black will work fine.