For optimal results yes. The reflector is specifically the piece of aluminium. Seen it as low as 40 bucks. Don't clean it with moist, or rub it, it's sensitive.
And yes, for optimal results, you should replace the bulb every year.
That is, however, not specific for "Gavita". If you don't replace the phillips DE after a year it will still put out more light than nearly every other bulb out there. And that goes for the german aluminium too, it will still reflect better than the materials used in inferior hoods.
The life time of LEDs also assumes professional application. That gavita will last, whatever the temp and the humidity.
Nice try RS but no cigar.