Players are limited to a certain number of each item. The number can vary based on the item (for instance, you can have only one weapon) or its effect on the player's load. As a rule of thumb, 99 should be the maximum number. However, it's up to how your game will use the item to denote its maximum number.

In the Final Fantasy series of games, Rule of '99 was used throughout its inventory system, allowing the player to carry no more than 99 potions at a time or anything else for that matter, as shown in the following screenshot:

A system based on the strength, endurance, and energy of a player is a faux-style system. It ensures that the player cannot carry more than he or she is able to; generally...