Bam, bam, bam, you knock on the door, check the smoke detector batteries, check for leaks under sinks, make sure the A/C isn't dripping inside, check quickly in the shower for mold, ask the tenant if there are any issues they need to report - and bam, knock on the next door.  

(Tenants would probably freak if the PM started taking photos inside the home.)It's normal to do an inspection twice a year, where the tenant is informed they will be checking smoke detector batteries and for plumbing leaks and to inquire of any other maintenance issues the tenant has. 

If the inspector knows you and trusts you they will often let things slide with a promise that you'll be right back with that battery or they'll offer to swing back by in an hour or two to check that you found a drain pan and pass you. 

We did inspections every 6 months, and told the tenants we'd be checking plumbing for leaks, and checking smoke detector batteries.  

How about smoke detector batteries.

We use a selection of Zigbee/ZWave aware locks, but predominately Schlage - the generation that did not try to power the deadbolt (powered deadbolts have shorter battery life and problems in older wooden buildings which shift in winter).

Hello - I have a 3 family rental house and I acquired a Kaba e-plex lock which is a commercial quality pushbutton lock with lots of codes, long battery life, etc.  

We now install the ones that have 10 year lithium batteries.

Do inspections every 6 months, but just put on the notice of entry that you will be entering to check smoke detector batteries and check for any plumbing leaks, and to please let you know ahead of time if there are any other maintenance issues you should look at while you're there. 

Look at the grid as a giant battery.