I bought 4 of these batteries back in February 2018 (a little over 4 months ago) and use them quite a lot to power various tools. One of the 4 developed an issue about a month ago where it stopped holding a charge and wouldn't power tools for more than 10-15 mintues when fully charged. For comparison using the other 6Ah batteries I can run the leaf blower for at least an hour; Similar short life using the string trimmer and chainsaw.
Dewalt replaced the battery quickly and with no hassle at all; took me about 5 minutes at the local Dewalt Service Center. I've been using the Dewalt 20V tools for about 5 years now. These are well built, high quality tools and Dewalt truly stands behind the product.