Notice in the upper right corner of the photo, a white cable tie is marking a sacrifice branch. I have started doing this when I designate a branch to be a sacrifice so I will immediately know what to do when I can back for the yearly pruning. This way, I don't have to reinvent my design each time. Of course, when the sacrifices get really huge like the one at the base, it isn't necessary, but for smaller branches, it's easy to forget that they are sacrifices and just prune them out or back without thinking about it, then you have to start over.
Of course, rediscovering the design each time can be a good thing as a mental exercise, but I don't really have that kind of time anymore, so I only redesign after a quick hard look. If I like how it's coming along, I leave it alone. If it doesn't turn me on, I start looking at other possibilities. That's why I say leave ALL the branches that have potential for either final branches or sacrifices until the trunk is nearly finished and you are committed. I have put over ten years into some of these trees, and don't feel any hesitation in starting over by chopping back to the first branch. If they aren't heading to really good bonsai, what's the point of going on? I approach this as if I am going to live forever. I am going to be 80 by the time some of these are done, if I haven't sold them by then, but I don't care, training them is the fun for me. I actually start to get a little bored as they start to get near completion.
Sacrifice branches are left in place until 1) they are finished doing their job, or 2) they begin to cause some sort of problem such as reverse taper, or will leave too big a scar in an area that you want healed over. What do YOU think? That large sacrifice at the base is intended to create buttress, has it finished the job? Not in my book, I will probably leave it for another four or five years. This isn't even the largest sacrifice branch I have growing. You can't see it from the picture, but some of these are 8 feet long and have to be staked up. After awhile it begins to get silly and I just can't keep the trees upright anymore, so I do hack back the sacrifice to make it shorter and more manageable, but generally you don't want to touch them except to keep them from shading the 'tree'.