ipod Battery Dying

The battery life on our (okay, technically it is Hubby's, but I've slowly staked my claim on it) ipod is slowly slipping away. The first indication was last month when I was out for my daily walk and the battery died after 40-45 minutes. Tried to fool myself by blaming the rainy weather, but today was sunny and it went silent after just over 30 minutes. According to my 10-year-old nephew (I'm trying to be a cool auntie), it's a first-generation and perhaps they have improved the battery-life on the 'new generations'. I really don't know why the batteries must die on these, except Apple will get more bucks from people buying newer 'models', I mean 'generation'. The only consolation is that the latest generation ipod does not have the annoying buttons at the top as they are not user-friendly. Now, I must find a way to justify the purchase of a new ipod to Hubby. If only Apple had discount sales.