A little bit about leveling in TFT
Your level plays a huge role in building your team's strength in TFT. Your level will directly influence how many units you have on the board at the same time and the chances of getting higher rarity units. There are 2 ways to gain XP: 1) You are given 2XP each round 2) You can buy 4XP / 4 gold
Generally, the 2 XP you get each turn should be just about enough for passive progression. However there are times in the game when spending a little extra gold can allow you an advantage that's going to make a huge difference. ***Bottom line: At any point, if you are only 4XP away from leveling up, SPEND THAT GOLD! Every time you level up, you are allowed one more unit on the board until level 9 (Max.) So do not lag in levels as it means lagging in fire power. Spending a little gold is definitely worth avoiding major dent i your HP. Another problem with lagging in leveling is you will have reduced chance of getting powerful champions. You know you have to reach a certain level before you can get epic or legendary champions. To create the best team you always wanted, pay attention to your level and invest gold when you have to.