leave (one) to (one's) own devices
To let one rely on oneself, without any help or other interference. I'm going to leave you to your own devices and see what you come up with without my input. It's amazing how some kids can really thrive when you leave them to their own devices, while others will be completely helpless.
leave to someone's own devices
Allow someone to do as he or she wishes. For example, Left to his own devices, he would hire someone to do the yard work. This expression, uses device in the sense of "a plan or scheme." [Late 1800s]