What an order costs

Hedera charges a fixed fee to schedule a contract call: about $0.12 (ScheduleCreate with a ContractCall, $0.0099 + $0.09, plus the 20% system-contract surcharge). That is 89% of a check, whatever the gas limit or delay. So the vault saves money the only way it can, by running fewer sweeps: each one waits about as long as the price needs to reach the nearest trigger.

Market	Checks at most every	at least every	assumed fastest move
HBAR / USDC	5 min	6 h	2.5% an hour
DAI / USDC	5 min	6 h	0.25% an hour

Cost, read from the vault (testnet rate, 1 HBAR = 7.7 ¢)	HBAR
One check, the only order in its market	1.8977
One check shared by 2 / 5 / 20 orders	0.9849 / 0.4372 / 0.1634
Reserve every order keeps for its fill and last check (HBAR sell / token sell)	0.8768 / 1.2371
Minimum budget	12.2633 / 12.6236

A market with a single order costs 7.6 to 22.8 HBAR a day depending on how far the trigger is, instead of 546 HBAR a day when it checked every 5 minutes. The Trade page sizes the budget to cover the order until it expires and shows the price of each expiry. Orders in the same market split the fixed part. Unused budget is refunded. The full model, with the measured gas per segment, is in docs/ARCHITECTURE.md.

The trade-off: a price that moves faster than the assumed rate is noticed late. The fill is still priced from Chainlink at the moment it happens and still guarded, and anyone can call executeOrder(id) or sweep(market, 0) to check sooner at their own gas cost.