Many towns etc are looking at the IBC 2015-2017 & here multi-units may be forced to install a fire sprinkler system with an alarm to the local fire hall.We always have a detailed inspection done & I only trust one guy to do it.

Tenant keeps complaining that fire alarm keeps going off when there is no cooking or any activity.

Inspect all plumbing, water connections, HVAC filters, smoke alarm batteries etc.

Things like upgrading wiring and plumbing, or adding firewalls in attics, fire sprinklers, alarms, soundproofing, wind/earthquake hold-downs, extra parking spaces...who knows...but you need to find out in advance and budget for those.Then there is the legal cost. 

I don't want to set off too many alarms until I know it will close. 

Wondering why you chose to never set an alarm? 

Oh boy, Alarm bells chiming...it's thin as you have observed, and one of the one of the advantages of multi-units that size is some economies with the one roof etc, but with the units split up like that...?

Because my mom is older, of course these calls alarm her.

It is very difficult to do business in regards to dealing with bad tenants and has increased the level of professional tenant to a alarming level.Landlords do fall to the mercy of tenants in any landlord friendly jurisdictions.

. ;-)I noticed the same thing that Michael B noticed when I read that particular post of Jonathan's - It jumped off the page at me like a big red flag; I could hear my 'BS detector' alarms going off (okay, maybe that was just in my head...).