For me, coding outside of work becomes unsustainable as you age. It's not that you can't, it's because you realise there's more to life than staring at a computer screen. I love coding, but it's also good to go outside sometimes.
Recent years (40's) I've been on a building spree of sorts for my own projects[0]
I'm my 30's, a lot of energy went into home improvement projects, establishing a garden, and young kids. Now I find a lot of time and energy left for my own passion projects.
