Yeh, you are probably right George its probably time to remove iPhone 4s from my flows! You've inspired me.

I would start by designing for the iPhone 4, 5 and SE width 320px. There is actually still a lot of people using those devices. Once you figure that one out the others are easier. Smallest mobile first then work up to the desktop sizes.

Hi Jeff,

This resource is usefull to check off all the things you can and may want to do for each phase of a project. https://uxchecklist.github.io/ It really helps to look back at and see where you are at. Also if you arent yet maybe start using a framework process in conjunction with the last resource to see what stage of the project you are in I find the Double Diamond quite good for this. https://www.thoughtworks.com/insights/blog/double-diamond

Good luck and hope this helps! Julio