Actually, the clutch fluid does not have an 'easy' job either, albeit not as tough (i.e.; hot/boiling) as right at the caliper pistons/housings.
But if you slip the clutch at all, do any drag race type launches, or sit in any amount of stop and go traffic jams, the fluid in the slave cylinder can be easily 'cooked', causing air bubbles, and the dreaded pedal stuck to the floor.
BTW; As I stated above, a local decent dealer (NOT the one I bought the car from in Doylestown!) has quoted me ~$120.00 for a full brake AND clutch flush.