It depends on your seniority and speciality. It takes quite a while to warm new team members into real productivity on mainline technical labor. Often, the first month or two of a new hire has a negative impact on total team efficiency. It's a similar principle to why you can't just staff up at the last minute before a deadline.

The exception is if you're an expert in some specialty that's relevant and underserved on the team. In that case, the relationship becomes more of a consulting role, where you do a very specific thing very effectively and in a way that it can be smoothly handed off to long-term maintainers.

Another opportunity is direct contracting for very early stage entrepreneurs. Building the prototypes or MVP's that help them understand and articulate their ideas. Even then, four months can be pretty narrow window in the real world and there's often a bias for people who'll stick around for the next phase.

One final possibility -- and the least reliant on other people's accommodation -- would be for you to just expand the period of your cycle. Can you commit 12-18 months at a time? That's actually pretty normal in the startup world, and if you manage your finances well, it can set you up for an equally long stint of solo work.