While I definitely feel investing in one's self is worthwhile. I am not sure if this is the right approach to think about the issue. The author compares the %

While I definitely feel investing in one's self is worthwhile. I am not sure if this is the right approach to think about the issue. The author compares the % of what companies spend on R&D and correlates that with what an individual should spend on educational material per year. I'd be more inclined to say it should be a % of your time. Instead of 5% of your salary, perhaps 5% minimum of your time per year should be spent towards learning. Though probably more is better? It'd be an easy trap to get into of spending 5% on "education/R&D" and not actually fully leveraging or utilizing it. One could blow that easily on a VM or server and some books and just feel like they've accomplished something when in reality they have barely leveraged what they have. Though if you are pursuing free/low cost education material, that small costs here and there shouldn't be fretted over.