I want to dye my hair ash blonde, but since I have natural kinda-dark brown hair it takes bleach. I've done this before and in the end I cut off my hair because it was so damaged. Then my hairdresser introduced to me a trick, she gives me highlights to lighten my hair and then in 2 months I go back for more. By the 3rd appointment my hair is ash blonde. MY question is, ...is this just as damaging as bleaching my hair then toning it with ash blonde colour? or is my method healthier?
Also, My hair is very damaged and very thin which means i need a shampoo and conditioner that gives it volume and keeps it super healthy....any suggestions?

Nope. It's not "just as damaging as bleaching" and then toning -- it's actually more damaging. The problem comes when the highlights overlap already-bleached highlights. Some stylists erroneously think that the hair will some how fix itself if you wait between bleachings. Unfortunately, hair -- with no blood supply and no "living" chemical reactions -- cannot and does not repair itself.

Damage to the hair is cumulative. Once the hair is damaged, it can only be cut off. It can't actually be "fixed" -- but see the next paragraph.

Claims for hair reconstructors and conditioners are highly suspect. Most are nonsense. Hair reconstructors are simply conditioners. Often they coat the hair. This strengthens the hair until it is washed out (the next shampoo). Conditioners lubricate the hair. They make it more pliable and the hairs slide across each other much more easily. This prevents further damage to the hair. It is essential that bleached hair be conditioned with each shampoo, but the conditioners don't repair the hair. When the conditioner or reconstructor is washed out, its effect is eliminated. If the hair is very badly damaged -- to the point that it's started breaking, the weight of the "reconstructor" (often "protein") will actually cause the hair to break faster.

Protein conditioner manufacturers often tout the benefits of using protein. I've heard a lot on newsgroups about "oh, your hair needs protein". In fact, hair is mostly protein -- but that doesn't mean that adding protein will help it. Most protein conditioners and reconstructors are made by hydrolyzing ground hoofs and hair from animals using boiling caustic soda (sodium hydroxide). The protein chains are usually three to five peptides long. This material will coat the hair, but it can't actually be incorporated into the backbone of the hair. It also washes out.

When you bleach hair, the natural pigment (melanin) lightens. There are some side reactions that break some of the chemical bonds between the peptides. These chemical bonds cannot be repaired.

The least damaging way to bleach your hair is to bleach it once, and every five to seven weeks, touch-up the roots. Don't deliberately overlap bleach onto the already-bleached area of the hair. This is difficult, but with experience it can be done.

When you tone, the better toner is an "acidic demi-permanent". It's really not very acidic -- the pH is slightly lower than 7, which puts it in the acidic region, but tap water is actually more acidic.

Google "Acidic demi-permanent haircolor" for brands.

Some people, who really want to keep their hair in good shape (healthy is used, but it's not accurate since hair can't really be ill or healthy), use temporary haircolors like Roux Fanci-Ful rinses to tone instead of traditional toners. Because Fanci-Ful rinses are temporary, they have to be used with each shampoo. The advantage is that fading is not a problem and damage to the hair is nill.