Can renewal of EAD be done 6 months before the original one expi

USCIS website indicates that renewal of EAD can be done 6 months before the original EAD expires. Have anybody ever done the renewal of EAD so early prior to your old EAD expiration? I noticed from some posts here that a couple of guys have the problem getting their EAD within 100 days. Thanks for sharing. Xiaobaitu, Radiology, and other experts, do you have any suggestions on that? Thanks!