Spring Forward and Fall Back. The time changes twice a year, so how can you, as a landlord, use that to help you manage your properties? One simple thing to do is to simply send your tenants a reminder of the need to change their clocks, and, at the same time, remind them to test their smoke alarms and change their furnace filters.
Want to do a bit more? Plan to use the time change to remind you to do the alarm test yourself. In California, you are responsible, as the landlord, to make sure that your tenants have operational smoke alarms and carbon monoxide detectors, so you really ought to do it yourself. That also gives you a chance to take a look at the general condition of the unit as well. Give your tenants notice and do a walk-through, with them if you can, to make sure everything is in good order. If twice a year is too much for you, plan to do it at least one time per year. This allows you to head off major repairs before there is a major problem.
You can also use the opportunity to change the furnace filter. While you can make the tenant responsible for changing the filter, if you take care of it yourself, you are able to be a bit more certain that it is being done. Keeping the furnace in good working order will help prolong the life of this very expensive piece of equipment.