if you think you will change your haircolour again anytime soon or wont be able to afford a colour correction or the hair damage if you dont like the colour, then only use a semi for reds. permanent red is an absolute beyatch to get out! i dyed my hair red red/brown for years and this year decided to get the red stripped and go back to close to my natural colour. its cost me an absolute fortune and its damaged my hair really bad.