I dye my hair a dark plum-black (was blonde) and do it every 4 weeks. I’ve been doing this for about a year. I’m worried about long term affects, such as damage to my scalp, loss of hair…

I’ve had no problems so far, my scalp is never irritated by the dye and it’s in fairly good condition as I use intensive conditioners.

I want to continue to dye my hair but how will this affect my hair and scalp?