AUM versus rate of weight
Newbies to big jet flying also find it interesting/confusing that a jet aircraft close to max landing weight must start its descent earlier (by up to 30nm) than one close to empty. A smaller rate of secent at the same Mach .85/340kts descent speed.
Using the 3 times rule with adds/subtracts for wind and weight were standard with us many years ago - don't see them much anymore :/