I voted for "always", but I need to explain this...

I find it extremely frustrating to use the N900 as a phone, so I end up taking my old phone with me all the time. The N900 is the same kind of "secondary device" that the N810, N800 and 770 were. - The way it is now, I have to pay €7,- a month for a second SIM card for this. If only the Finns had provided a clean way to tether the N900 with a phone the same way I could with all Maemo devices before, I'd never have a SIM in it.