I always say to myself don't worry about speaking up, if something doesn't seem right or you are not happy tell them, if they are offended then so what. Sometimes it pays to be a bit ruthless, but i am always polite.
I used to worry about offending others and hurting their feelings, i learnt that they don't seem to bother about that then why would i. I mean most of these people who will help you, you are paying and will never see again.
Also provide as much detail as you can upfront, that way if they ask for more money and you have proof you told them about it before hand, how can they charge again. Spend time and don't feel rushed by anyone.