I'll also add that with an electric guitar, it's totally normal to practice without amplification. If you're playing non-distorted parts, and your room is quiet, and you're not totally deaf, an unamplified electric guitar is loud enough to be heard well, while not being loud enough to be heard outside the room. Playing distorted parts doesn't work so well, however, because you can't really hear all the harmonics very well without the amplifier, and the distortion changes the sound so much.
