how easy to renew

It's possible for you to extend the current type 7 days earlier before it expires. You should first prepare your passport, valid registration form of temporary residence, the application form, a passport-style photo, as well as other materials the consular officers consider necessary. And then submit the application to the exit and entry administration of the local PSB to apply for the extension. If it can be done, there is no need to leave China. You can try it! Good luck!