Serviced - depends on the type.
Manual hubs you know for a fact that they are engaged or disengaged (or broke )
manual hubs you can engage them and drive all day, week, year - long if you want.
They don't care but your gas mileage will be decreased while engaged due to the extra parts spinning causes drag...
Unless your unique and install manual hubs in the rear you will only have hubs on the front axle...
( Yes, I have manual hubs on front and rear of my Jeep - flat towing it cross country got better gas mileage with the tow vehicle that way)
12 F150 Lariat 5.0 4x4 Crew
03 Edge 4.0 -Next door
Y2K TJ Sahara... Lifted, locked, loaded
08 Scion tC