leave to chance
leave (something) to chance
To resign oneself to something's outcome being determined forces outside of one's control. My boss always scrutinizes the smallest details of any deal she makes—she says there's nothing more foolish than leaving things to chance in business. You could just pick a few different investments and leave the whole process to chance, or you could let our firm plan your investments meticulously in order to maximize your return.
leave something to chance
to allow something to be settled by chance. Plan your day. Don't leave anything to chance. It is not a good idea to leave any of this to chance.