People ask if I'm available and if I find the work interesting and they can pay me I say yes. I have never looked for work since starting and have slightly more requests than I can fulfill (almost everything through my network). For efficiency I do full days of work + ad-hoc meetings when necessary and no more than 2 days per week per client.

Note that I'm not always a CTO in the strictest sense of the word, I like doing complex technical challenges with software companies and sometimes just lead a complex project like implementing ISO 27001 or re-packaging a software suite for on-prem deployment.