Degradation of materials and constructs seems like it would be necessary in order to sustain a player-built economy IMO. Otherwise, scarcity would continue to be forced downward, as would prices. Entropy is a fantastic sink, and I really like the idea, especially allowing for wide variation across materials/components/etc. Don't want to grind on repairs? Pay someone a fee to cover the market price for mats and overhead of repair systems. Or keep spares. Don't have a trusted mechanic? Buy your own mats, bots, and equipment and cut out the middleman. Don't have the money but lots of time? Hack together your own manual repairs and patches (or have your pet do it) - just enough to keep the lights on. Or, live dangerously as some have suggested and do absolutely nothing - your cheap ship may blow up but you can always buy or build another one. As long as the methods are economically balanced this should be fine and should suit lots of playstyles. Entropy could also (eventually) make for some VERY interesting planetary mechanics for example the need to build ships differently for use on different planets - corrosive atmospheres, extreme heat/gravity, etc. My #1 concern would still be the player economy though - in order for this game to work at all the economy needs to be *real*, for all intents and purposes.