I also have an abundance of detectors of both types, and I hardwired them so no lapses from forgetting to change batteries.

Technically you can make an excuse like check smoke alarm batteries, replace furnace filter, etc., but a determined tenant could push back on that too and say that they will tend to those things. 

First let me say this- if it is more than replacing light bulbs, batteries and filters I don't let tenants touch anything.

If you keep the property up, and do inspections every 6 months, change smoke detector batteries, meet codes, etc., I can't imagine anyone having a multi-million dollar successful suit against you.  

I used to be an onsite manager less than 6 months ago in CA so that would be my feedback.the other stuff is not that important, it won't net much gain in rents.your annual maintenance is critical on each unit  - caulking, changing flappers and batteries on smoke detectors, co detectors and changing air filters.

The Leafs are pretty cheap and their batteries last a long time and are not that expensive to replace.

The only thing I allow my tenants to do is change out the smoke detector battery and the indoor air filter.If pay the repair yourself, just keep a record of what was done and if it happens again in the near future then definitely do a tenant charge because that would be in excess of normal wear and tear.I hope that helps and good luck in your decision! 

I didn't withhold their entire deposit which I could have, but they did have to buy paint and all supplies for me to recondition the home to smell like a freshly painted home again.

Then a guy popes out of their unit and says to my tenants "Thanks for the battery bro".

Emergency Contacts and Guidelines If something needs to be repaired or replaced:Please contact xxxx, LLC by sending a text message to xxxx at 303-xxx-xxxx.If you do not receive a timely response, please also try 303-xxx-xxxx.Fire, medical, or police emergency:If it is an emergency call 911.Please replace batteries in smoke and carbon monoxide detectors as needed and leave them and the fire extinguisher(s) in place.