Thanks Bob. I have a bunch of apps on my iPhone 6+ but have not used them enough to judge what is useful or not yet. I have the 128 GB model so I can hold quite a few and I have been downloading things that look interesting.
For people with newer models there are some video and photography apps that are worth having.
1) Ultrakam $10 this lets the iPhone 6 use all of the cameras capabilities to shoot 4K video. It also gets the most out of some older models. For the 5s for example "Ultrakam allows you to record 2K film resolution video in your iPhone 5S with nearly uncompressed quality." http://vfxwarrior.com/ultrakam4k/#!home
2) Hyperlapse by Istagram: This app lets you shoot stabilized time lapse videos that look like those achieved through the hyperlapse process. The results are really cool. https://hyperlapse.instagram.com/
Look on Youtube to see how to access secret setting in the app.
3) GoPro app: If you have a GoPro camera there is a GoPro app that lets you connect to the cameras wifi and view and control it remotely.
4) ProCamera: $5? This app lets you control various aspects of exposure, white balance etc on your phones camera. It will let you take by giving you more control. There is the real;ity bowever that the iPhone camera is a fixed focal length and if you zoom in, it is a digital zoom with loss of quality.
5) Battery Doctor by KS Mobile Inc. seems to be a useful utility to monitor and regulate your battery charging on the phones.
6) Data Monitor - Manage Your Usage byAmos Epstein - monitors your data usage for the month both through cell and wifi.
I have a bunch of Apps most of which I have not even used yet, or only fired up to see if they work.
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky