One other time you'll need a lot of storage is when retrofitting an entire fleet which has been out on mission long enough for weapons/sensor/ECM tech to surpass it. Of course, you could just build tons of new ships and keep sending the old fleet out until it dies. It's not nice, but, hey, who ever won a PBW game by being nice to their people?

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The Unpronounceable Krsqk
"Well, sir, at the moment my left processor doesn't know what my right is doing." -
Freefall