Writing my own script has several advantages. First, writing my own script gave me a simple project to begin learning Ruby, something I have been wanting to do. Second, it allows me to extend the script with functionality that might be clumsy in a spreadsheet. Right now, I am just keeping track of the same information that I did in the spreadsheet, dates and weights, only I track it in a simple text file. The script calculates the sliding average for me. If needed, I can easily munge the data in other ways or pull together a secondary text file with other information like my workout routine. I know that I could do the same thing in a spreadsheet, but I like the flexibility that a full programming language gives me over the comparative restraint that I feel when I am hacking together formulas in a spreadsheet. Additionally, my data is kept in a simple text file instead of being tied to a Numbers spreadsheet.

Finally, and most importantly, I was easily able to pull in a library that allowed me to plot my weight and the sliding average of my weight over time and export it as an image file.