The most common problem when using faucet sites is small payments or dust or micro payments. Because every time you received a Satoshi from faucets to your wallet, you will have a new input that you will send it later or sooner. Imagine if you have a lot of micro payments received from faucets and once you make a transaction to send to any Bitcoin address. It will composed of different inputs, example, if you will send 0.005 BTC to address B, then you have many micro inputs from faucets that will compose in a total of 0.005 BTC. Remember that, the more inputs in a transaction, the larger the transaction fee. Same with, the larger the size of your transaction in terms of size per byte, the larger the transaction fee.