This is a fantastic list for anyone in their 20s. The only blunder I didn't do in 20s was to get too many credit cards, still on one credit card that I had, I ended up paying heavy penalty due to my laziness to keep track of my expenses on that card. I also didn't do any investments in my 20s so that was another financial blunder. A third financial blunder was to buy a ULIP fund rather than an index fund. A fourth blunder was to stay in one company for too long, at only 5% annual hike while my peers got up to 50% hike upon switching to other companies every two years or so.
I haven't even started on the health and career blunders that I've done and the opportunities I lost on alternative careers.
I can bet you my list is longer. :P