JTP, I think you're pushing your luck...
10 years is way too long on rubber parts - they age regardless of mileage or usage. Given the inexpensive nature of the parts and the criticality of failure of those parts, I'd swap them out ASAP if I were you... I'd hate to hear that you overheated because you didn't change a $20 hose.
I did the hoses on my 2002 last year, because I had to change the thermostat anyway (it had stuck) and I had them loose. Did the belts as well at the same time. Even if the thermo hadn't failed, I would have replaced them by now anyway.
2002 Z3 3.0i