Two flows, one balance
Every currency in a game has a supply that is created and a supply that is destroyed. The sources are called faucets, and the drains are called sinks. The total amount of currency in the world at any time is the accumulated difference between the two. If faucets run faster than sinks, balances rise. If sinks run faster, balances fall.
That sounds simple, but the reasons designers care are practical. A currency that is plentiful stops motivating players. A currency that is too scarce stops being fun to earn. The aim is usually a middle zone where players always have something to save for and the ability to buy it within a reasonable time.
Common faucets
- Quest and mission rewards
- Enemy and chest drops
- Selling items to non-player vendors
- Daily login or weekly bonuses
- Season or event rewards
- Currency granted by systems such as a battle pass
Faucets are easy to add, because players like receiving things and designers want rewards to feel generous. This is why they tend to accumulate over time. Every new feature wants a reward, and each reward is another source of currency.
Common sinks
Sinks are harder, because players do not enjoy losing currency unless they get something they value.
- Repair and upkeep. Equipment wears down and needs paying for.
- Consumables. Potions, ammunition and buffs get used up and bought again.
- Upgrades and crafting. Fees, materials and failure chances remove resources permanently. Upgrade success rates, in particular, create a sink in which failed attempts destroy part of the cost.
- Transaction fees. A percentage taken on every sale between players.
- Cosmetics and status items. Items that carry no power but are worth buying for appearance.
- Fast travel, storage and convenience. Small, frequent charges.
The best sinks give the spender a choice or a visible benefit. A repair bill is a tax on dying. A cosmetic shop is a sink people choose to enter. Designers generally prefer the second type where they can, because forced sinks tend to be resented.
A simple balance example
Imagine a game where a typical player earns 500 gold per day from all faucets. Over a 30-day month they earn 15,000 gold (500 x 30). Now suppose the sinks, including repairs, consumables and optional purchases, average 400 gold per day, or 12,000 over the month. The player’s balance grows by 3,000 gold each month. After 12 months, that is 36,000 gold (3,000 x 12), assuming nothing changes.
If most items cost between 500 and 5,000 gold, a balance of 36,000 means the player can afford almost anything at will. The currency has stopped doing its job. This is the situation designers worry about: the average player may be fine, but long-term players drift into surplus. The numbers are illustrative; real games differ widely in rates and in how varied players are.
Averages also hide the spread. Active players may earn five times more than casual ones, so a sink tuned for the average can be trivial for some and punishing for others.
Fixing a surplus
When balances grow too large, teams have several options, and each has trade-offs.
- Add new aspirational sinks. High-priced cosmetics, housing or prestige items give accumulated currency somewhere to go. This is the gentlest approach but only works if players want the item.
- Raise prices. Quick, but unpopular, since players feel they have been charged more for the same thing.
- Reduce faucets. Also unpopular, because it looks like a cut in rewards.
- Add percentage-based costs. Fees that scale with balance or transaction size bite harder at the top.
- Introduce periodic resets or conversions. Some currencies expire at season end or convert to a different one at a stated rate.
Teams generally try to make changes gradually and explain them, because sudden shifts can feel like punishment. Many designers also prefer to avoid destroying value that players have worked hard for. An approach known as soft sinks offers choices rather than confiscation.
The opposite problem
Too many sinks can be just as damaging. If repair costs and fees eat most of a new player’s income, they cannot buy their first upgrade, and the game feels like a treadmill. This often affects newcomers more than veterans, because veterans have savings and efficient routes. Some designs therefore apply sinks that scale with progress, charging little early on and more later.
Why it matters for the whole economy
Faucets and sinks do not stand alone. Prices in a player market respond to how much currency players are holding. When balances rise, sellers can charge more and buyers can pay it, which feeds game inflation. The overall picture of how currencies, rewards and spending connect is covered in broader discussions of the in-game economy.
Randomness complicates the picture. Drop rates and pity timers affect how much comes in, while crafting failures and item farming routines affect how much goes out. Designers usually look at long-run averages, knowing that individual players can see very different results from the same system.
Reading it as a player
When a game introduces a new fee, price or reward cut, it is often an attempt to restore balance between faucets and sinks. The question to ask is whether the change moves the game closer to a state where saving, spending and earning all feel meaningful. Judging that takes time and is a matter of opinion, but understanding the mechanism makes announcements easier to interpret.