to a meeting at which one is the client, but in a personal not a business capacity? Like with a mortgage advisor/accountant/cosmetic surgeon etc?
My head says I am the client and as long as I don't turn up in filthy rags with a crack pipe in my handbag I can wear what I like, but my heart says I ought to be appearing "professional", and I have no "professional" clothes as am self-employed.
I'm nervous about the meeting so focussing on trivial stuff 
(It's not a cosmetic surgeon.)