I'm a mid-30s senior engineer as well. The type of problems I solve now are completely different than the problems I solved in my early 20s. Back then I spent

I'm a mid-30s senior engineer as well. The type of problems I solve now are completely different than the problems I solved in my early 20s. Back then I spent considerable time grinding out dozens of very similar things. These days I figure out how to handle a problem and then some person in India grinds out applying that solution all over the place. Grinding out cookie cutter code takes less effort. I could do that more, but I can't really use my brain more. It wears out too quickly.