Replying to How do I know when the boot fits???

Now, with a completely moronic title like that, I expect the replies to pour in.

I have decided to get a proper boot fitting after skiing in boots that never really fit me. My question is this: What should I expect the new boots to feel like?

Yes I will be fitted (hopefully well), but I want to know what to expect. Should the boot feel perfectly broken in the first time I put my foot in? Will I know the boot is the "one" within seconds? Will I need to compensate in my mind for how much it will pack out? How much is acceptable play between perfect fit, and what it will be with a few days on the slope?

I knew the moment I put on the last pair of shoes I bought, that I *had* to have them. Should the boot be like that?