When to Automate

I'm just pondering something that I think about fairly often when I'm asked to do some immense task like create output for 2,256 watersheds. That was today's task ... and by “today” I mean ... I'm not going to finish it today, it was just added to my inbox today. I have to use the 2001 NLCD to create forest/non-forest data and then clip out a piece for each of the 2,256 sheds to run Fragstats on. What I wonder about is how much of this can I automate with a script. The answer usually boils down to efficiency. I mean how much time would it take to write the script vs. how much time would it take to do it manually. Usually there are several steps (as in the present case) so I have to answer the question for each step. Sometimes a script can be useful in the future so it may be worth writing one even if it takes a little longer to write than to do it manually (because it will be so much quicker next time you have to do a similar task). Anyway I think with the shear number of times I have to do this, I'll need a script or two. Wish me luck.