I make sure led lightbulbs are in all fixtures and smoke detectors have active batteries.

Smoke detectors, GFCI outlets, handrails, working heat and hot water, etc.

I was required to add exit signs in the shared hallways / stairs, and to add interconnected heat detectors in all units, and to upgrade all smokes in all units to be hardwired, and to create 1-hour fire separations between the three units, which we accomplished by painting the ceilings and walls shared with stairwells/common halls with intumescent paint.

New heat sensor smoke detector because the old one went off any time the stove was used.

When I first bought this place,  was an LP heater in the living area at one time, so the detectors include the CO option. 

yes, we pay as soon as we get the invoice....hard to know if we are getting scammed on pricing though...for example just had 2 bath sink faucets installed with under counter shut off valves, and replaced a defective smoke detector...charge was $433,  of which $48 was parts  (not including the faucets....)

I always replace toilets, shut off valves, water fixtures, add frostproof water spigots with additional isolation valves for winterizing, switches, light fixtures, Add ceiling fans to every bedroom, GFCI outlets, regular outlets, smoke detectors with 10-year or hard-wired-in, use a quality one coat semi-gloss paint, basic white washer/dryer and Exterior door locks with touchpads (key free). 

Like the roof, and anything else, ignoring maintenance will only increase expenses for later repairs.Spring and fall are great times to inspect the house, and while batteries for smoke detectors can be left to the renter, replacing those, or water filters, etc, are great reasons to inspect the property.

@Alvin SylvainThe system uses a password breach detector, and your current password may have been breached.

WLB has not only the lease, but at least a dozend other forms and notices you need (aplication form, lease, rules&reg, non-standard lease providsions, lead disclosure, CO and smke detector notice, pet agreement, 5 day notice, lease renewal etc.