What about armor?

In your mecha games, do you prefer armor to wear down, or is that too much bookkeeping?

Do you like armor to offer variable protection in different places?

What ideas and mechanics make mecha armor interesting? Stuff like multi-layered armor, brittle armor, ablative armor, reactive (exploding off) armor, energy-vulnerable armor, electrically-fortified armor, etc?

Whatcha got, gearheads?