So despite being naturally dark brown I do suit blonde and look younger more polished etc with almost all over colour. My issue is that once it gets to a certain length, just past my shoulders and is blonde hairdressers want to cut it off, siting the condition as their main reason, I don't think it looks bad but they always chop it off .... Is there anyway of doing this from scratch .... Again .... Without trashing the condition ? I'm even considering keeping it collar length and blonde and just wearing clip in Extentions every day as a solution.
Are you having highlights, and if so, bleach highlights? If so, when you go to get your roots done they will inevitably re-do bits that have already been done. Over time this will trash your hair and I can see why they want to snip it off.
If this is the case one option would be to have a base colour of a high lift tint, which if dark brown would probably bring you up to at least a light brown or dark blonde, albeit a warm tone. You could then have bleach highlights but less of them, and less often, to give you the blonde look.
I have light brown hair and tint my own hair up to a level 9, which is for me a warm blonde, and then have occasional bleach highlights to break it up and lighten round the front, and my hair is in much better condition than the days where I had highlights every 6-8 weeks just to do my roots (and a hella less expensive)
I definitely recommend extensions to fill out the ends and boost your length though, I have them sometimes, just 50 pieces and its lovely and natural looking when its just that many. I am lucky because i have a hairdresser friend (school mum) who puts them in for £50 and I buy the extensions from the wholesaler for £55 so its not an expensive thing. That said I haven't done it for over a year, my hair is in pretty good condition and a good length now so I haven't felt the need.
You have to work really hard on maintaining good condition so you don't have to keep losing the length as the damage travels up the hair shaft. Protein treatments, very gentle, sulfate-free shampoos and no heat styling.