Should I bother to try a subwoofer?

My speakers are listed as going down to 40 HZ (Dynaudio 1.3 MkII monitors).
There is an REL Strata III available locally that I might snag, try out and re-sell if I don't like/need it. My question is this: since I would not be using this for movies, do I even need this? I mostly listen to classical music, more chamber than symphonic, and occasionally listen to rock, jazz and other pop styles.

Am I likely missing something without that lowest octave? I'm thinking that 99% of the time the sub might not even be in use if it kicks in at 40 Hz.

Any comments, purely theoretical or from experience, will be welcome.