When you run your program for the first time in two months:
- A beginner has no idea whether it will run or not.
- A journeyman engineer will assume that of *course* it will run properly. It's just code, after all, and I haven't touched it, so duh -- nothing has changed, so why wouldn't it work right?
- An experienced systems engineer holds his breath and prays when he says "run", because he knows the 75 different forms of bit rot that can set in in the span of eight weeks. (OS updates; remotely-fetched libraries that have disappeared out from under you; forgetting the correct procedure to start the program; IDE "fixes"; or simply the machine deciding to be ornery.)