One problem we had specifically was when we leveled up our characters. Our maximum HP increased, and our DM changed our token's values to reflect this.
However, our player tokens on other maps weren't updated along with this, which slowed things down a bit when we changed maps. What needs to be done is have a master-token or master-character from which others update their characteristics from.
In programming, this is known as inheritance. Think of it as something that is the same amongst similar things, like apples. You have Granny Smith, Red Delicious, etc. You don't have to learn what an apple is all over again to understand Granny Smith if you already know Red Delicious, because you already know characteristics common to apples.
Likewise, 'child' tokens have all the characteristics of 'parent' tokens. The only thing different between them would be which map they are located on.