Everyone has different ideas of the perfect wedding hair. Some want it down some want it up and others want both. My advice is to do what works for you and your wedding vision. My other advice is to practice what you want. You probably have a vision in your head of exactly what you want. If you do not practice, then how will you know if your hair stylist has the same vision.
I am the perfect example of what not to do. Way back when I got married, I was not experienced at wedding planning. I showed up on my wedding day and told the stylist what I wanted. When he was done, it was not what I exactly wanted. Best of all, my cousin (who was just a guest) had her hair done, and it was exactly what I wanted. The good news is that my hair looked good and the hair was not a big deal for me, so I did not stress.
Are you going to have the same reaction that I did if your hair is wrong? If you really want a certain look, then you need to have a practice session. Take a picture if you find one and talk to your stylist. If she or he is not doing what you want, tell them. They do not know what you are thinking until you tell them.
My only other advice is be cautious about leaving your hair down. If you leave your hair down with curls, will it hold? You may say, yea I have gone to events and my hair has done well. If your wedding day starts at 8 am to get your hair done and your reception is going to 11pm, it may be up to 14 hours. Will your hair last that long? You can still wear your hair down, just know it may not look picture perfect at the end. As long as you are ok with that, then go for it.