Mobile suits (MS for short) are produced and destroyed at a extremely high rate (with the exception of unique units). This is very unfortunate for pilots, since 90% of MS are not equipped with eject pods, leaving most to die in a big, purple explosion.
Non mass production MS are upgraded regularly for no reason whatsoever. This allows them to obtain, most commonly: flight, giant energy cannons, and energy shields as time passes.
Common MS include Arm Slaves, Knightmare Frames, Gundams, Zakus, Variable Fighters, LFOs and Evangelions.
"Holy crap! There are mobile suits in there!"
*At the Mobile Suit Research Institute*
"We're being attacked by a massive mobile suit force!"
"Those fools! Launch the special unit!"
*Mobile Suit Attack Force*
"What is this place? Hey! There's a sign over there!"
"Everybody run! Its the mobile suit research centre!"
*Special unit shows up and destroys the raiders in one attack*