The halo portable charger and jump starter stays charged for up to 6 months without use.
If you haven't use the halo portable charger and jump starter within 6 months you should plug it in and let it charge up just to make sure it's charged and ready to go.
I've had my halo portable charger and jump starter in my truck for 6 months without using it and then I needed to use it to help someone else jump start their vehicle and it was still ready to go.
I still keep a pair of jumper cables in my truck just in case I need to jump start someone else but so far haven't had to use them much.
The halo portable charger takes around 6 hours to fully charge but should last 6 months without needing recharged unless you use it before then and then if you use it then you'll need to charge it.