Overuse of
- Do you know Aggron's weaknesses?
- 4x Fighting - 4x Ground - 2x Water
Yes, it has lot's of resistances, but hink about it. Most people nowadays carry at least one strong water Pokemon/pokemon with earthquake. (eg
OR 
)
Is it worth sacrificing? EVen with moves such as protect, you cannot last forever. I have to sleep, so I'll add more later.
----------------------------------------
I'm back!
Tip #2
When building a team, use moves that cover a good range.
Bad - Swampert with HydroPump, Water Gun, Surf, Dive
Good - Protect, Surf, Earthquake, Ice Beam
------------------------------------------
Tip #3
It's not all about the offense/defense.
Bad - Blissey with Return, Egg Bomb, Ice Beam, Facade
Good - Toxic, Reflect, Ice Beam, Sofftboiled