These are FAQ’s about me and my contest history. You might also see School FAQ’s.
I never kept track because the number wasn’t important to me, but a very rough guess is perhaps 10 to 20 hours a week, with a large standard deviation (because I only practiced when I felt like it). In practice the number might have been a lot higher, because I would often think about math in passing (while walking between classes, sitting on the bus, etc.). It’s harder to quantify how much or how effective this kind of time is but the “shower” time certainly seems quite important.
But seriously, don’t count hours spent, it’s not a helpful metric. Even “number of problems attempted” would be a better metric (provided they are at the right difficulty), although I think that this number is pretty uninformative as well.
As I said it probably doesn’t matter too much which ones you choose, as long as you exercise some basic common sense. I think it’s useful (and more fun!) for students to decide the fine details of their own training, rather than e.g. reading a specific book “because Evan Chen used it”. (On the other hand I have no objections if you use a book “because Evan Chen wrote it”!)
If you’re looking for suggestions for materials, try my recommendations page, my own handouts or my geometry textbook. These are at the olympiad level; younger students would likely benefit from books or classes from Art of Problem Solving, like Volume 2.
I live in the United States, but am also a citizen of Taiwan, where both my parents are from. So in the spring of 2014, I flew back to Taiwan to participate in the IMO selection process rather than going to my high school classes.
I started training seriously starting in the 2009-2010 school year, when I was in eighth grade. I had participated casually the year before that.
See my teaching page for more details.
It is hidden somewhere on this website, on cofinitely many of the pages. ;)