Most African countries suffer from poor and inadequate power supply and as a result of that, their use of power banks as a means of having power for their smartphone always charged is on the high increase.
Personally, I'm making use of Oraimo 22,000 mAh power bank and it serves me for at least one week if it's fully charged.
I have two power banks but I haven't used them yet. My wife got them because we don't have outlets by our bed and if we didn't feel like plugging our phones all the way across the room we figured we'll just use the power banks instead.
I haven't used a power bank for a long time for my phone. I remember the last time I used a power bank was in around 2017 or 2018 when we all went out as a family and we all were playing Pokemon Go and catching Pokemon whilst out for a walk and going to a music festival that day. Due to the battery being drained as fast as it did with Pokemon Go a power bank was very much needed at the time.
Power Banks have been helpful for me over here in my country. It is another source of energy that I can use when my mobile device is down. Sometimes, the epileptic power supply don't always help matters.
I have two power banks. And these power banks are almost like an essential part of my daily life. I go with them anywhere I go to. And I make sure that I charge it when I have the chance to. It helps my phone to always stay on in the face of unstable power supply.