My current doorbell at home has lasted me for 28 years (since 1985) and hence I got a new SoundTeoh No. 77 Wireless Doorbell from Funan’s Challenger for S$28.60 (member’s price: S$25.74).
28 years later, it seems technology also changes doorbell. There are so many types right now: wireless, wired, AC powered, battery powered, mp3 (using SD card) and 20 built-in tones.