In update 3.2.1 a new feature was added, the Arsenal Bonus. The Arsenal Bonus permanently increases your health and attack for each new rarity of an equipment piece. It increases by 0.25% for each new rarity.
| Rarity | Cumulative Increase |
|---|---|
| Common | 0.25% |
| Uncommon | 0.50% |
| Rare | 0.75% |
| Epic | 1.00% |
| Legendary | 1.25% |
| Mythical | 1.50% |
| Exalted | 1.75% |
| Deluxe | 2.00% |
If you have every single piece of free gear at deluxe then you can get a max Arsenal Bonus of 26%, and if you have every piece of gear, free and premium, at deluxe then you will have the maximum Arsenal Bonus, at 84% for 42 equipment pieces.