Glossary term Retention
Endowment Effect
The tendency to assign more value to things simply because we own them. Accumulated streak counts, XP, and rare items are all subject to the endowment effect, they feel more valuable because the user has them, not because of their intrinsic utility.
Where you see this in practice
The mechanics that lean on it
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Streak / Streak Bonus
A counter that increments each time a user completes a defined action within a set time window, typically once per day.
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XP / Leveling
An experience point system where users accumulate points through actions, eventually reaching level thresholds that unlock rewards or status.
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Set Collection / Completion
A mechanic that organises rewards into named sets, where completing a set unlocks an additional reward or status.