One thing guaranteed to prompt a CAPTCHA is enclosing several words in full-quotes, or else using inurl: or intitle:
This has had a chilling effect on my searching in general, and I observe that when work is done and I search for more general things (that are presumably easier to monetize), the CAPTCHAs go away.
It has got to the stage where I resort frequently to Yandex and other search engines which censor and prune far less than Google now does, in preference to DDG or Bing, which seem to follow the Google playbook quite closely.
Does anyone else here have a similar experience of being CAPTCHA'd while trying to get work done and make use of the more advance operands?