I replaced the battery on my iPhone 6 when the $29 offer appeared from Apple. For about 3 months, the new battery really made a difference - it charged super quickly and lasted all day. I've noticed in the past 3 weeks that things are slowing down again (e.g.. takes forever to load my Facebook pages), and the battery is only lasting about 1/2 the time it did when I first replaced it. Is anyone else having this issue, and if so, what have you been able to do about it? thanks.