NHL Waiver Wire

I found the official rules to whether a player has to clear waivers or not. One of the great mysteries of the world if you ask me, but here it is:

There is a sliding scale that is used. Players that are signed as 18, 19 or 20 year-olds are essentially exempt up to age 23 and 160 games. Then, as players reach the NHL at older ages, the requirements drop
21 year olds -- 3 years, 80 games
22 year olds -- 3 years, 70 games
23 year olds -- 3 years, 60 games
24 year olds -- 2 years, 60 games
25 year olds, one year exempt.
Goaltenders have lower games played requirements (from 80 down to 60) and go a little longer in terms of being exempt