A video below demonstrates how you can freely destroy your own computer and crates without consequence, however go to a roommates room, or shoot up some heavy equipment aboard a friendly space station and watch your penalties mount up. If you get into negative credits your credit score turns into a debt.
Shooting at friendly NPCs will also incur an Assault Penalty which is higher than the basic Vandal Penalty, and murdering NPCs can fine you as much as 10,000. Killing a essential NPC, like one of your crew results in immediate death and game loss. Additionally, Assault Penalty also includes an experience deduction. However, property animals like cows count as vandalism.
Abandon vehicles and enemy owned equipment is free to be destroyed, just be careful you're not reclaiming an area like the shipping port you start in. It may be invaded by Droids, but the vans and forklifts still belong to friendly NPCs. You have plenty of warning before an item is destroyed and the full penalty is given. A stray bullet into someone's furniture or van only cost you a credit. Although keep in mind using stronger weaponry does cause more damage. The Blaster can pretty much destroy anything smaller than a forklift in a single shot, so be careful what and who you shoot at!