Gaming theory: Random interval reward mechanics

Random interval (or often: Random drop) is a player reward mechanic commonly used in games. From board games utilizing shuffled cards or similar elements to the complex arrays of digital games, random interval is used to simulate spontaneous occurrences of rewards in order to add to the excitement of player efforts in the interim of gameplay.

Like many a term in gaming, it is difficult to cite an accurate source or precise definition across platforms, genres, or gaming sub-cultures for its "random drop" alternate name. I'd suggest the term came into being from the nature of the rewards and the most frequent appearance methods of these rewards; being occasional and often difficult to rationally tie to their sources with appeaing in the gaming world on the 'persons' of defeated foes or their immediate area as if 'dropped' from possession.

Cons
Can fail to be desirable by players with specific goals or those whose characters cannot effectively use the reward
Rarity of specific rewards becomes artificially greater as the list of alternate rewards increases
Often requires inventory management and liquidation efforts in order to make rewards useful
May trigger impulse control issues similar to gambling due to player market demands, wider range of reward values, and inconsistency of rewards to player efforts

Pros
Incredibly easy to design, program/implement, and expand upon
Can be a very effective means to promote player-ran/player-participant in-game markets
Excitement factor of more desirable rewards can aid in extending play duration

Commentary
Random interval rewards have a number of other instances aside of the more apparent; likely any time that there is a chance of variation in instance rewards for player efforts, they are interacting with a random interval mechanic. Some random interval systems also have a randomized chance of rewarding the player either due to sharing rewards with cooperative players or by adding a null reward option.

Random interval reward systems should very rarely (if ever) be used for progression systems as they will force players out of comparable or competitive capacity at no fault of their own efforts.

One way to think about random interval is that it's a simplified mechanic that tries to remove consideration of player specific goals and needs and offers a single system that rewards players approximately equal values of rewards for approximately equal efforts.