Handwritten? No, it's not hard, but it can take a while - some of those codes can get really lengthy. It can get really annoying if you have to redo it. That's happened to me many times before, I would copy down a column of code, and would make a stupid mistake, like putting in a 7 for a 1. Then I'd start it up, it wouldn't work, and then (since I wouldn't know where the problem was), I would just put the entire code in again.
Luckily, there aren't many codes that are really long. Most of the codes that I use are maybe 5-20 lines, at the most.