Being interpreted allows modifying programs and then restarting (using GOTO) in the middle of a run, even multi-day, without losing accumulated data. Stopping is not recommended unless a program has been saving the data safely somewhere, or if users forgot to write any way to save data when quitting (perhaps they did not expect to find any and were trying to prove it). When doing anything that might lose valuable data, or if you need to do something else for a time, then you can FREEZE the current program to a file and later MELT it (as long as the lower memory configuration is the same).