Hi, native speakers of English! I've just read another thread with the title 'one less thing to worry about'. The explanation in said thread is perfectly clear, but somebody told me it should be 'one fewer thing to worry about' if we wanted to be grammatically correct (just as in the difference between 'less people'/'fewer people'). Is 'less' here informal and accepted, yet incorrect? Should we use 'fewer'? Thank you in advance.