Wayne Parham Messages: 18879 Registered: January 2001
Illuminati (33rd Degree)
No, voice coil unwinding isn't normal wear and tear. In most cases, it will never happen. I have some old radios with speakers that are nearly 100 years old and they still work fine.
When a speaker is overheated due to excessive power levels for a period of time, the adhesive that glues the winding to the bobbin begins to fail and the coil unwinds. This is failure mode that is caused by overdriving the speaker.
As long as you don't overdrive the speaker, the voice coil will stay intact for decades.