"The Science & Craft of Designing Daily Rewards" is the latest post on Bill Grosso's Expert Gamasutra blog, where Scientific Revenue's founder and CEO explains how free-to-play games can optimize this mechanic to increase retention, while also providing background on the behavioral economic principles at work. For instance, here's Bill on optimizing a consecutive reward feature:
Like Jerry Seinfeld’s “Don’t Break the Chain” strategy for creative success, this mechanic encourages players to make it a habit of consistently claiming rewards. (And I can personally attest to its motivating effect: my son wakes me up every day to "do dailies" in Clash Royale, our current favorite.) However, there’s a downside to this model: When a player forgets or is too busy to claim their reward, they generally break the streak and get pushed back to “square one” -- a demotivator which players often interpret as a punishment. At this point, many players often just give up on the game as a whole. One effective solution: Include a daily reward schedule in the game’s user interface... That way, players are reassured that they’ll quickly get good rewards soon after starting over at square one. My Singing Monsters displays a reward schedule built around a five day cycle (above).