If you make a transaction on the Ethereum network, you will be asked the price that you are ready to pay in gas. The higher you put the value, the faster your transaction will be carried out because miners will be interested in processing your transaction in priority. The gas limit will allow you to set this amount.
In this context, the gas limit is a protection that will allow you not to spend more than your maximum. But you must put a minimum amount for your transactions to pass. If this is not the case, the transaction will not be carried out because no minor will provide you with its computing power. So it's up to you to adjust the amount of gas for an Ethereum transaction.
You're in a rush ? Then increase the price of gas and your transaction will be quickly processed. Are you making a non-emergency money transfer? You can put the minimum amount necessary for the transaction to be carried out. Rest assured, the ETH wallets all offer a predefined default amount to ensure transactions.
You can always consult the ETH Gas Station website for the ideal amounts to insert, which depend on the congestion of the Ethereum network.