Sustain is usually the length of a note heard through the amplifier. Sustain is usually associated with the higher output pickups that generate more current to the amplifier and often becomes more distorted than lower output pickups. I like the sustain associated with medium weight woods of an instrument, solid bridges and pickups adjusted about 1/16″ on the bridge pickup and 3/16″ on the neck pickup. I find that using pickups with stronger magnets and hotter wound coils can dampen the string vibration but cause more distortion in the amplifier. There is a sacrifice you need to make with tone and output.

I still think of the tone you hear with standard pickups used by Stevie Ray Vaughn, Jeff Beck with The Yardbirds and Jeff Beck Group, Eric Clapton with The Cream, Jimi Hendrix, Roy Buchanan, Albert Collins all using standard guitars and pickups. They didn’t use super sustain pickups and they had the tone.