Ten years ago, I asked Cell companies to let me have more than one phone on the same number. Recently I noticed the ability to almost do that with Google Project FI cell service.

Project FI is a cell service done (mostly) right. Low $20 basic cost, no phone subsidies or lock-in, fairly priced long distance, pay for data as you use it, roam on multiple networks, but most of all, the same $10/G data price in almost the whole world, at 3G and sometimes 4G speeds. It's not perfect -- it tends to roam with smaller carriers, it has problems sometimes overseas, and $10/G is a high price for those who use more than about 3GB/month of data.

I recently noticed a new feature -- you can get up to ten extra data-only SIM cards at no extra cost. You pay for the data you use, as always with this plan. You can get a SIM for a tablet, but I think even more useful is the ability to pick up extra SIMs for your old phones. Now you can use these old phones as backup phones. Keep one in your car, to use if you forget your phone in the morning. Keep one at the office. Loan one when you travel.

The trick that makes these work as phones and not just data devices is project FI links your phone number into hangouts. If anybody calls or texts you, it also comes in via hangouts. So if you have decent data, you can take or make calls and SMS on the phone with the data-only SIM.

It's not perfect. Sometimes calls over data suck. There is a small cost for the data for the voice -- probably about 1 cent/minute. That's actually a big savings over the one remaining roaming charge they have -- 20 cents/minute.

Now my old phones can have a purpose. Old phones are old, though, so you want to strip out the apps you don't need on a backup phone to keep them zippy. You will want to leave them in airplane-mode-wifi-on when not actively roaming with them so they don't use your data plan sucking down emails and facebook.

BTW, if you are wondering if $10/GB is a reasonable price compared to plans that give 5 or 6GB in their basic $40-$50 price, I have found it to be quite reasonable at home. That's because when I am home, I am on wifi in my house and most of the buildings I visit regularly. That keeps my data load down. When I travel, I try to go on wifi in the hotels but I also use the phone a lot more, and I will use 3-4GB in those months -- but that's a much better price than you will get from other carriers. T-mobile's plan gives unlimited roaming but only at 2G speeds which are very low utility.

(BTW, while I really love the fact that incoming FI calls and texts go to hangouts and thus my desktop and laptop in addition to my extra phones, the Hangouts program is an absolutely terrible phone interface, lacking even redial and call-back and other very basic functions.)

Project FI is not a big network, and it's other main flaw is that it only officially supports the Google phones like the Pixel and Nexus, though you can use other phones unofficially without quite as much roaming. But it's also a great competitive push on the other cell phone companies to price in a manner that makes more sense. Cheers to them. (Disclaimer: I own some GOOG stock and am friends with Google management, and consulted there in the past.)

Keeping it in the USA

One serious flaw in FI, though, is that they don't want people who live outside the USA to get it. One presumes they are not making or even losing money on the international roaming, and making it back inside. I spend 3 or more months a year outside the USA, so I may not be a profitable customer for them.

The problem is that to stop foreign users, they will only activate a SIM card if you are on the US networks. So if your phone fails while you are on a trip, and you have to replace it, or your SIM fails, you may be in a pile of trouble -- you won't be able to get and activate a new phone while on your trip. This hurt me when my Nexus 6 got unreliable on a trip. I had to put up with a crashing phone. It's possible that had I begged they would have let me activate a new phone, but uncertain. Official policy is not. On the other hand, you are not entirely out of luck. You can get your new phone, put a local (ie. non-USA) SIM in it, and still get your calls and texts via hangouts, or via forwarding at some cost.