Ease of spectrometer operation is understood to mean:

a) Spectrometer hardware maintenance:

a1 Recalibration intervals

a2 Electrode cleaning frequency

a3 Stand cleaning frequency

a4 Entrance lens or window cleaning frequency

b) Comfort

b1 Spectrometer operation while standing or sitting

b2 Arrangement of controls

b3 Adjustability of operating parameters

c) Software convenience