A  mobile device is called ‘mobile’ because the intention is for it to be taken with you and not carried about. We want to be able to flash out that device in an instant, check something on the web, and return it to our pocket.

In referring to ‘mobile device’, I am referring to anything from a “dumb”or smart-phone to a tablet.

For lots of people, there is a delicate balance between the convenience of a generous screen-size, versus the inconvenience of its over-generosity.  While most people would want the screen to be as big as it can get, there is a point where that bigness impairs functionality. If it is too big, you might as well go along with a netbook / laptop. A 10” tablet makes NO SENSE to me!

In addressing what the screen size should be, software developers (for both the OS and user applications for mobile devices) have a duty to make it possible to seamlessly allow users to choose font size. This is primarily applicable to Authors of Mobile Browsers,  E-book Readers and mobile WordProcessors.

To buttress this point, my mobile browser of choice (UCWeb 7.4) allows me to select a font size that is really comfortable for my eyesight. It is noteworthy that the maximum character size on the phone (when running UcWeb) is actually bigger than that selectable on my netbook (10.1”) when running OperaMini on the netbook http://mobilitynigeria.com/2010/10/26/save-some-money-browsing-on-pc/

I mentioned this to emphasize the point that a bigger screen-size does not automatically translate to bigger / more legible font. It is the duty of the software Authors to make good use of that screen ‘real-estate’

Lots of time, there is a correlation between the screen size and the available (virtual-)keyboard.

It is an irony that while everybody would prefer the biggest screen and biggest keyboard, a device offering such convenience  loses its “portability-appeal”

For me, I feel that optimal size for a truly mobile/portable device would be about 4.5” (diameter). It would give me that delicate balance between functionality and convenience.

Anything bigger that, and we are creeping into the realm of being unable to fit it into the glove compartment of a small car or  a jacket / trouser pocket. Anything more than that, and you will definitely need two-hands (all the time) to make use of that device.

Try to carry something that big to your ears – to make/receive a call.

How more ridiculous can that get!

What about you?

What would be the ideal size of your mobile device, keeping in mind the likely battery-life impact, single-hand-useability and ability to carry about in pockets (due to size/weight?