Wail - why doesn't hair dye last on my hair?

[BlueBottall]

So, I've got naturally mousey/dark blonde/light brown wavy hair. I used to be blonder when younger (I'm 50 now, and post menopause, if that's relevant), and so usually dye my hair to a similar shade from my youth. I use a golden blonde colour - Nice and Easy, permanent colour. Suits me and doesn't fade, I just need to redo to cover my roots.

However, I have hankered after going red. Not bright copper red, just ginger/strawberry blonde. I've tried twice now. Used two boxes of dye both times, but each time, the dye has faded even from the first wash, and by about a month later, my hair doesn't look at all red/ginger, just a murky light brown.

I can't afford to do a salon job, so any suggestions as to why this is happening and what I can do to get lasting red hair as I do when I go blonder?

Thanks in advance!

What colours are you using? Reds do fade quickly. Do you use shampoo/ conditioner for coloured hair?

Reds are difficult, I've been fake red for over a year now and it still needs redone every 4-6 weeks to remain red. I use salon colours which helps - wella colourtouch and koleston in my case. You also need sulphate free shampoo and at least a weekly colour depositing conditioner

Hi
I've just used the Nice and Easy dye as the blonde has always worked so well. It comes with a conditioner to prolong the colour, which I use once a week as advised. I use a colour shampoo otherwise, and only wash my hair twice a week .

I didn't know reds fade quickly. Why is that?