dashiichi: I hadn't realized that the cosf of repairing each succeeding slot increases. That really makes the bother of tracking down a crashed ship not worth the effort. Pity, I was getting pretty good at solving the numerical series questions!
Repairing slots is actually cheaper than trading-in the ships. That's because the trade-in will be about 50% lower than the initial value you have paid. That's confusing because both are marked as ship 'Value' in the game. But it's easy to verify: just buy a ship and compare it with another one (without accepting), you will see that your ship value is highly reduced.
I start with junk ships and exchange them with better crashed ships until I have what I want, then I repair the slots once i have the final type I like. That's only about half the slots of the final ship, quite expensive but still cheaper than trading-in.
The guy who has set this in the game must be a broker or something, such people always think in % :=)
XenonS