I've played a few games of Bolt Action and feel I have a pretty good handle on the rules. In fact I rate the rulebook very highly indeed. As I said in my review it's the only set of rules I've ever been able to read through in one sitting. Usually my eyes glaze over after a few pages as I try to assimilate the masses of detail.
But, unless you're Sheldon Cooper, you can't remember all the rules from one read through. So generally you just check things as they come up in a game. However doing things that way means that you can miss things. So I like to keep a set of rules handy and read a couple of pages when I have a spare minute. This way it helps reinforce things in your mind but also it highlights things you may have missed.
As I said I feel pretty confident with my understanding of BA but in my latest quick foray into the rules I noticed this little gem regarding the special rule that some weapons have called 'Assault'. I've always thought that it just meant that those weapons got to roll two dice instead of one in close combats. But I just noticed that you also don't suffer the -1 for shooting while moving. Somehow I had completely missed this and it hadn't come up in any of my games. So without re-reading the rules I might never have found this out and playing with the same group of people means that rules pretty soon become locked in as we 'know' how things work.
So keep a copy of the rules handy to dip into when you have a spare couple of minutes. You never know it might mean the difference between victory and defeat in your next game.