I heard somewhere, but forgot exactly where, that the German C-Netz mobile network back in the 1980's was the first network that separated subscription from device via a SIM card. Since then we've come a long way and all major mobile network standards these days have implemented the concept. From my point of view this is the most important thing to foster competition between network operators.
As a frequent traveler I use lots of different SIM cards for both voice and data and I love the concept of just inserting a new SIM card into my devices when I arrive in another country or when better and cheaper offers become available.
Evidentce of this is the heap of SIM cards I've decommissioned over the last couple of months as shown on the picture on left:
- Two years ago, SimplyTel in Germany, a MVNO of T-Mobile started a pretty good voice minute offer for the time. Unfortunately, they haven't kept pace with others and there is still a good data option missing. Also, they've started to introduce a 1 or 2 euro fee per month if the SIM is not used which bugged me since I used one in the block heater of the car for incoming calls only and the other one in a mobile I give to visiting friends from abroad. Now that their accounts have reached 0, I've retired them and replaced them with SIM cards from other MVNO's.
- The AT&T SIM: This one's a forced retirement as I haven't been in the US for 6 months and the SIM has probably been deactivated already by AT&T.
- The YESSS SIM: About 18 months ago, YESSS started a prepaid mobile broadband offer in Austria with a validity time of 12 months. In the meantime the year has expired and I have made good use of the offer. Now, however, I've replaced the SIM with one from A1, as they have started a similar offer in the meantime and their network has a wider reach.
- The A1 SIM: This is the SIM I replaced the YESSS SIM with. Adding a further GB worth of data traffic is 5 euros more expensive than buying another SIM card for 15 euros that already includes a GB worth of traffic. A bit strange but then I don't really care if I buy a top-up voucher or a new SIM.
- The WIND SIM: This Italian SIM card was deactivated and I haven't quite been able to figure out why. I went to a WIND store but there they could not really help me and told me to call the hotline. I decided it was faster to dump the SIM and buy a new one instead. Much less trouble than to discuss the matter over the phone with a helpdesk lady.
So in short: SIM cards = Power to the consumer!