Your claim is worthless without context. Please provide some evidence: why is smartphone the highest ROI purchase for you and why do you think it will be worth it for others.

With smartphones as ubiquitous as they are today, computer-literate people who don't have them should have their reasons. You don' t provide any.

My reasons for not having a smartphone are: I predict that benefits of smartphone ownership will not justify the cost of ownership for me. The cost of ownership consists of:

One-time:

• Researching and choosing a smartphone
• Learning to use it and its many applications
• Cost (smartphone must be bought)

Recurring:

• One more thing to manage and obsess over
• One more thing to charge and not lose
• A distraction that's always with me. I cannot do any productive work on the phone, but I can use the internet, very slowly. Any time and energy spent on it would be better spent elsewhere.
• Data plans cost money.

Of course, smartphone usage has its well-documented benefits, but for me they didn't yet outweigh the costs.

The reason I ultimately surrendered and bought a smartphone was that I hoped to implement Allen's GTD with it. Only later I came across his interview where he advices not to use brand new technologies for GTD, but tried and true ones, that you are already comfortable with. So true.