I was reading The Economist (recommended for anyone interested in how the world works) and I came across an insight that I hadn't really thought about before. From an economics perspective, the younger you are, the more benefit you get from discovering something new that you like and therefore the more willing you should be to try something new. This would be true of a new technology, new food, or really whatever.
So what does this have to do with human factors? Think about who you are designing a system for. If it includes a large population of young people, you can sell the fact that if they like it, they will gain many years of enjoyment. If you have many older people, you want to sell the conservative aspect of the design - it takes little learning so they can start enjoying it right away, or something like that. So when you are collecting user requirements in general, you want to think about your population age and customize the requirements specification along these lines. When you design the system, make sure it is either easy to learn for old people or adding new functionality for young people.
Of course some young people are conservative and some old people are willing to experiment, but in general this wisdom should hold up. The example in this post was a coffee frothing wand. Ironically, it is what I got my dad for Father's Day last year, only I spent a whole lot more than $1.99. Where was IKEA when I needed it ;-D.