I'm 31 and unfortunately going rather noticeably grey. It started when I was 25ish and I began dying it the same colour as my natural hair, occasionally with some highlights.
For various reasons it's been about 5 months since my last 'do', and unfortunately my roots are significant, 2-3inches, and the grey is obvious! But having not seen my own hair in years, and being as it costs upward of £60 for a salon cut & colour, I'd rather like to let it be. My only concern is that I'll look weird whilst it's growing out, and I'm also worried I'll look old, so I thought I'd ask DH's opinion, essentially to get reassurance that I was fine to leave it be.
But when I asked DH (who is also going as grey as I am at 30), in short he said that he thought as I was only 31 I should dye it as I'm a bit young to be going grey. I said that I didn't really care what the general public thought, but that I minded what he thought, and he said he thought it looked nice when I dyed it. But, said I, being as I don't really want to dye it, and it costs as much as it does, then why should I have to pay for it? And he said that he thought I took money for hair out of the joint account, and if I didn't, I should, he didn't mind.
I asked how he'd feel if I said I didn't like his going grey and tactfully left some Just for Men out, and he said hadn't asked me what I thought of his... 
Right. So when I get my hair dyed, I now don't have to pay for it from my personal pennies (it'll be a house 'expense'), and my DH has made it clear that he likes it dyed, so am I being unreasonable if I still don't want to, mainly on the principle that I should be able to do what I like with my own hair?