World of Tanks is both an incredibly rewarding and an incredibly frustrating game, depending on what goals you set yourself. It also heavily rewards you spending money. But spending money helps very little in winning battles (although one might argue that a few of the premium tanks you can buy are overpowered, certainly not all of them); however spending money helps enormously with you progressing along the tech trees. Ridiculously so, I would say.

I am currently doing the Top of the Tree event, which gives various bonuses, rewards, and discounts if you move up one particular tech tree. This month it is the Japanese medium tanks. It is just August 3, and I am already at tier VII, because I spent some money. Normally a player who doesn't spend money gets double xp for his first win in any tank, and quintuple xp for his second win if he is playing a tank of the current Top of the Tree line. For 10 bucks I get those quintuple xp also for the third and fourth win. Plus I still had some extra "5x XP" bonuses from previous purchases. Having a premium account gives me 50% more base xp (base xp means it is then multiplied by all those 5x bonuses). And 5 times per day I can add another 3x base xp after any victory. So I had games in which as a free player I would have gained 700 xp, and because I had all those bonuses I ended up with 10,000 xp. Okay, that is only for the first handful of wins, but it is a huge boost. 100k xp doesn't look so daunting if you make 10k in a single game sometimes.

The other big boost comes from the so-called "free xp". Normally one gets very little free xp, e.g. my 10k xp game only gave 51 free xp. However any xp you make on tanks that don't need xp anymore, as in fully researched tanks and premium tanks, can be converted for gold into free xp. I always wait until there is an event on which gives a better exchange rate, 40 free xp for 1 gold, and then I spend a pile of gold. As a result, whenever I get to a new tank in any tech tree, I don't have to drive around with it stock; I can at least spend the free xp for a better track, engine, and gun, so the new tank already starts with competitive equipment. I don't spend the free xp to research tanks, but skipping the stock tank grind is already a huge boost.

Now normally with such good progress in the external rewards / level structure of a game, I should feel like a king. Instead I still feed like a n00b, after over 10,000 battles. The problem is that at the higher tiers I often get into games in which the average player has already 30,000 battles and the good players have much more. Normally in a PvP game after some time you don't feel like a n00b anymore, because there are lots of newer players that are clearly less skilled than you are. In World of Tanks there hasn't been much influx of new players, and "new player friendliness" is rather a weak point of the game. Veterans do more to scare new players away than to attract them, by farming those new players in low tier games for stat padding. So I don't often get into a situation where the knowledge and skills I have certainly acquired over those 10k battles actually lets me outplay somebody lacking that experience. It's a Catch 22 situation, because other new players certainly experience the same, that they never really progress visibly towards veteran status, and thus they leave, making the problem worse.