I self-published eight (non-technical) books. They sell reasonably well, at least by Czech standards (just 10 million speakers), but the first one sold the best

I self-published eight (non-technical) books. They sell reasonably well, at least by Czech standards (just 10 million speakers), but the first one sold the best, around 10 thousand copies. The latest one only sold some 2500 so far. This might be a post-Covid effect, though. During Covid, books sold well, people were probably bored. Post-Covid, with high inflation kicking in (we are around 17 per cent in Czechia), people reduced their cultural expenses first: food and energies are more important. That said, I found the combination of being a programmer and a writer fairly efficient. Being able to write documentation in detail beforehand means that I discover a lot of subtle problems and corner cases before I actually implement something. And, as a practising writer, writing documentation feels easy to me, a natural flow.