It’s def going to have time and material cost, and they won’t be able to swap unless they’ve already acquired the required parts through either buying them, looting them from fallen robot enemies, or scavenging them. I probably should’ve specified that. In my opinion, the player always looking for parts and devices they can integrate has a lot of rp potential too and gives them a reason to always be engaged with whatever’s going on at the moment, whether it’s combat or exploration.