Depreciation expenses

Capacitors set in the rectifier and ripple smoother of power supply circuitry in two tube low frequency amplifiers were replaced into new one after 30 years production. New 3 capacitors costed around 1,500 yen promptly. 

But the result invited no regret but brilliant praise in the quality of the reproduced sound. As the reduction of the performance in capacitors occur so gradually as difficult to discern the performance degradation. 

Generally speaking, the original performance would be lost in 5  years use. 30 years use is too much at all? Remember that the most decayable parts in the electric circuitry in nothing but "Capacitor" even in the computerized generation. 

Another idea guides me some conclusion that so to speak braking time for replacing electric equipments in natural commercial distribution economy. Due to taxation, it is necessary to record depreciation expenses periodically.

Digit Kyoritsu and Sengoku situate at Nipponbashi Osaka supply electric small parts even now, the place is an equivalent to Akihabara in Tokyo. 40 minutes train ride takes me to the place, it is very convenient for E-hobby player, recently generation changes customer bases, so the seller said to me.