What is the GAS Limit?
π¨βπ Gas limit is the maximum allowable consumption of conventional units (gas) to pay the commission for the current transaction.
In other words, it is your consent to use gas in the specified amount or less.
If you manually change the gas limit and specify a value less than that required to complete the transaction, then this operation will not be completed, and the commission will be spent from your wallet! The error will look like: Out of gas
It is not recommended to set a lower gas limit, despite the overestimated MetaMask (or other wallet) forecasts. You will not gain anything from such manipulations, and in most cases you will probably pay twice. If you send a transaction with an inflated gas limit, the network will not charge you more than is required to confirm your transaction. Surplus will always be returned back to your balance. Usually, the limit is 300,000-700,000 Gas.
Follow this video to set up Gas Limit in TrustWallet manually:
To better understand how GAS works in Ethereum - a great example is the gas for a car.
GAS LIMIT - amount of gas needed to travel the specific distance (aka mpg - miles per gallon), or how much gas your car spends on 1 mile. And if you run out of gas in the mid way you just stop and your gas can never be returned as it was used, but was not enough to get to the "destination".
GAS PRICE - is how much the gas costs. and it determines the priority of your transactions in the network
Gas Limit is required so that in the event of an erroneous request with a closed loop, all the money from your balance will not be spent on endless attempts to do something that cannot be done on the Ethereum network for any reason.