and it works well for me. I just create "To Do" lists on my iPhone. I have a "To Do-Immediate" list, and a "To Do-Long Term" list, and I toggle between them as necessary. You obviously could name your list whatever you want. My phone is always with me, and so are the lists. And I've learned how to imbed photos into the list when I need a specific product spec or model number, etc.
It's simple, and it works for me.