I use a single device most of the time. Eliminating the need to sync calendars/mail/contacts/… across devices greatly reduces my dependence on big cloud providers.

On the other hand, I mostly work on open source software, so all my work is publicly available in timestamped commits. It is easy for anyone to guess my working hours, timezone, and time off. And all the comments I write can tell you a lot about my views of the world.

I think the privacy impact of open source is not talked about enough.