I suppose as a (very rough) rule of thumb, if a phrase requires a certain level of sophistication or education, it would in theory be used less. Educated people would be more inclined to use structured phrases that contain jargon (e.g. I want to take my pants in), whereas a less educated person might just say things as a matter of fact (e.g. I want to make my pants tighter/smaller). This is very much a generalisation though!