We used drop-ins for about 8-9 months before the holders started melting/warping in the bottle warmer at daycare... But anyway, we always washed the nipple and ring and gave a good rinse to the holder.
We wash the nipple and ring everytime and rinse the holder unless I can see formula on it. We will wash the holders a few times a week though...just not every feeding.
Re: Repost: those that use Playtex DropIns
Jennie