I'm currently looking for jobs and I would love for it to be a four-day affair (reduced hours, not full hours squeezed into fewer days). I value free time way more than the money I can get for it and besides I genuinely believe I can offer the company way more productivity if I have more space outside work to get involved in my own projects instead of getting burned out with the monotony of a 40h-week grind.
It's worth noting that the four day thing is not a hard line on my side. I would be willing to work full time (and overtime) for the right company with the right mission etc. but otherwise I'm pretty picky. I would consider a sub-optimal opportunity if it includes a four day week. That's why currently I think a salary negotiation period might be an appropriate time to discuss this, kinda as a way to communicate "offering me more money won't make me more likely to join, but fewer hours will". But there are other options too - maybe it's better to be completely upfront about it and risk the companies being discouraged from pursuing interviewing me, or maybe its better to be patient, establish myself at a role and then ask once I've proved myself?
About me: I'm an embedded software dev with a pretty strong background but in an awkward phase of having a couple of years professional experience but not enough to consider myself a senior dev. The location is non-London UK.