Let’s have a look at another player-positive monetization mechanic – Boosts with Duration

The idea is simple. Players pay to get some sort of bonus for a limited time period. Most often those are in-game currency or experience bonuses, helping to speed up the introductory period of the game, which is particularly useful for experienced players building a new character in the game. Here are a few tips for making your boosts work:

• Do not make your game too grindy to incentivize the purchase of boosts. Gamers will notice the connection, and they will hate it. 
• Offer an opportunity to bank the leftover boost time after exiting the game.
• Throw in cosmetic bonuses in addition to experience or currency.

Done right, those can also help with player retention, as it will be a lot easier to try new builds and characters with a boost.