from my point of view i think is better to have log for staff/client that way we can know wich staff has deleted a service, something like that
staff id X deleted service XXX
staff id X edit service XXX
client id X updated contact id XXX
client id X logged out
staff id X added service XXX
we have do something similar in our notification plugin, but it should have so many improvement to achieve a total loggin system, as now we only logging what events return . we have the attention to analyses POST request to add more actions/info to our actions, but we don't have ETA for it.