My smartphone is an iPhone6s that I bought at Hong Kong airport.
I was using an iPhone4s with 16GB before, so I thought 16 GB storage would be more than enough for this new phone. I like my new iPhone because it doesn't make a shutter sound when I take photos.
I installed the same applications I used with iPhone4s, but somehow the free storage soon became less than 1GB. I checked the storage and my photos were taking a great part of it. The photos required much more storage than before.
I did whatever was recommended to reduce the storage, and the free memory increased to about 3GB, but one day my phone started dying when the battery had 44% left. I found out that it indicated 44% but that actually it was 0%.
I backed up the data to a PC, ran the recovery on the iPhone, then put the data back to the iPhone. It started working correctly again. At the same time I checked the storage size. Almost 50% of the total storage was now free.
Now I do a backup and recovery from time to time. Some settings, like ID touch, have to be done again as well as line stamps download. Still, it's a good feeling to have my iPhone working better.
I also have a 64GB iPad mini with a lot of applications. I don't even know any more what is installed. The iPhone6s has minimum applications so it is easy to use, but I plan to get one with more memory next time.