As long as you stick to non-routine aspects of your life, is there really a limit to how many items there should be in the list? You got to do what you got to do… The key is probably to set priorities, and do try to tackle those pesky items.
I don’t limit my ToDo list, but I pick out of it three most important things I must achieve that day. Most of other things either get transferred, are short and get done during breaks or don’t survive
S L Na Q.
I, personally, love the feeling of checking things off. So I break up my tasks. I never like to put more than 15 but I always just do the main priorities.