Small leak on faucet

[Matthew King]

So I'm a new landlord so I'm learning things very fast.  I never expected being a landlord to be a hands off gig and so far things have been going well.  The rent, which is on the higher end for this area, has been paid on time every time and with good communication from the tenants.   They also have been good at keeping the house in order but my question is specifically in regards to a very small leak on one of the bathtub faucets.  This faucet has leaked for a while, before they moved in actually, but in order to fix it I will have to rip out the wall behind it.  It doesn't leak when shut off, only when water is running.  

Should this be something I should feel compelled to fix (I can't do it myself so would have to hire a plumber)?