Good quality for the first one, two or several orders, but lower down the order quality after your orders become stable.
Frequently chat with the supplier online if you have time, just like you are seeing someone, the more times you are seeing him or her, the more you know him or her.
Start with several fairly small orders, and test if the supplier is trustworthy.
Must keep the original samples the supplier sent you, and check every order quality by comparing with the original samples.
Once you find the quality problem at the first time, tell them what you want now or next step.