The key to healthy coloured hair is to keep your strands moisturized and hydrated with the right hair products.
Its important to use products made specifically for colour treated hair that help with the hairs pH balance and moisture.
With pre-lightened hair, blondes or over processed hair it's important to restore your strands back with protein followed by a moisturizing conditioner,
this helps with the Ph balance.
To keep your colour vibrant and from going dull use colour stay shampoos & conditoners or (temporary colour) cellophanes in between your colour retouches.
For healthy hair be sure to keep your strands properly moisturized, conditoned, trimmed and on a good haircare system.
If it is too much for you I recommend you pay a visit to a licensed hairstlyist bi-weekly.