I bought a Anker PowerCore Fusion 5000 2-in-1 Portable Charger and Wall Charger (AC Plug with 5000mAh Capacity, PowerIQ Technology, For iPhone, iPad, Android, Samsung Galaxy and More) a while back. I haven’t used it that much as a portable charger and lately started using it as a wall charger. Is there any detriment to it being plugged in all the time as the charger will get to 100% charged but still plugged in.
I would use it as a power bank to drain the battery once a month to 25% and keep it out of direct sunlight.
If you don’t travel with it, I would suggest like the previous post, cycle the battery (100%-0%-100%) once or twice per month. The battery is in better condition if the current flow through it regularly.
Two things that are bad for batteries: heat and topping off to 100% frequently. Since you don’t use it as a power bank, no worries