@bastl:
That's exactly what I meant :-)

@bonerp:
I don't agree on that. I manually check my mails now every half an hour ... and at lunchtime my N900 is online on 2G/3G for about 2 hours. This way my battery lasts a few days. Other ways (always connected) it just lasts one and a half day ;-)

A further idea would be an app, that establishes & cuts your connection automatically after an adjustable couple of minutes. Preferably fully adjustable in daytimes .. e.g. "from MO - FR 8-12 am and 14-18pm establish internet connection every 30 minutes & close internet connection after idling 3 minutes" :-D