My question is, should we be responsible for that $75 dollar service fee, for a simple battery replacement?

Lever battery powered coded lock.

Does the clicker just need a battery or?

The advice from the HVAC Guy that put the boiler in, was to leave the old manual T-Stat, because if a tenant moves out at midnight in January, the heat will still work, because they dont require batteries, like the digital ones do.  

Batteries in smoke detectors are $2 each.

(Please make sure they have working batteries.)All kitchen fixtures and appliances should be in good working condition, including: faucets (should run hot and cold without dripping or leaks), oven/stove (all knobs and burners should be present and working, and the stovetop free of grease), refrigerator (make sure it's clean, and that the lights turn on and the doors shut properly), dishwasher, garbage disposal, lights, drawers and cabinets.Water heaters need to be working (and if placed in the garage, need to be placed on a platform 18 inches off the ground), have earthquake straps, and a properly installed pressure release valve (with a discharge line directed downward that reaches six to 24 inches from the ground).Heating.

In the two years the girls lived there, the only expenses we've had so far are:gutter cleaning for $40 register the home with City of Raleigh $60Disposal + handyman items yesterday - $450Cleaners - $100HVAC filters, smoke detector batteries, CO2 detectors - $60

I have the fancy car - a Mercedes SL500 convertible - that it driven so little that I had to charge the battery yesterday.

And we do all of these, replacing batteries and making notes of maintenance issues.

Check smoke detector batteries, provide a CO detector, put a fire extinguisher in each unit, carry adequate insurance, install hand rails, have a solid lease, get a big balloon policy and do the right thing.