The one-man-company design workflow

For simple projects, I prefer a different workflow
1- Lay out the schematics with the most important components
2- Draft mechanics and place core components
3- Add more items to the schematic diagram
4- Adjust mechanics if needed
5- Place and route the new items
6- Goto 3
7- Add anything optional that may be useful and fits mechanics
8- Place and route these extra things
9- If something else fits, goto 7
10- Remove unused "options" before the mounting step

Everything must be performed with later steps in mind
Please consider the cost and software effort of anything you add
Please wonder what the client/user may unexpectedly ask
Think about mechanics, power consumption, heath, noise, ...

And please be helpful to your software mate
I/O channels, logging, debugging, ...