nikon and dust

[deadshot]

Another question for you nikon users,is dust a real issue ?.A dealer told me he has been using a D80 for two years frequently changing his lenses and has no sign of dust.!! I would be leaving my lens on all the time and I would say I use my cameras an average amount.( not professional or photo club member)Also is cleaning sensors a big deal?At the moment I use a bridge camera.Panasonic FZ7.The Oly E510 seems to have class leading dust prevention do you consider it is now a must have?.

Thanks for your comments