[KenWittlief]

one of the design criteria you should be using to evaluate different design approaches is servicability / repairability, or MTR (Mean Time to Repair)

simply put, if your frame is damaged, how easy will it be to repair? how long will it take on average?

dont paint yourself into a corner thinking there is no way your frame could be damaged. Bad things happen, crates get dropped off trucks and forklifts from 8 feet up, Robots fall off tables and carts, or down stairs. When something bad happens to good robots you will need to repair it, then the question is: will it take 8 people 4 hours, or 40 hours?

If the only approach to fixing a welded frame is to bring a complete spare frame, then thats what you must do. How long will it take you to transfer everything on your robot to the spare frame? Or it might be better to fasten the frame members together some other way. or maybe have welded subframes that bolt together?