4 years from now seems reasonable. It all depends on how much life there is in the DS. I don't see the chance of the DS dying within the the first 5 years. And chances the popularity of the DS will die off is only dependant on how well the competition is doing! As far as the PSP goes, there's no real competition and when it comes to software sales... the PSP is a joke. Nintendo need not to worry to bring out a new handheld soon. Unless the PSP comes with a true successor. Nintendo needs to launch the next system around the same time. With Sony introducing a redesign instead of a new system means they tend to keep the PSP alive for a long time too. And they are putting all their efforts to make the PS3 more profitable than to invest in a true successor for the PSP.
