In addition to the other comments (which are correct) keep this in mind also.
When claiming furniture as a rental asset, via safe harbor or not, your state "may" consider that to be a different type of asset that is subject to a tangible property tax for each year that furniture is used in the rental property to produce income. So it's perfectly possible for what you "save" on federal taxes by claiming it as such, you'll just end up paying to the state *EVERY* *YEAR* in the form of a tangible property tax. In some states (my state of FL included) it's the county that imposes a tax *every* *year* on any and all tangible property used in the production of income.
Also, when you convert a primary residence (or other personal use property) to rental property you have to update your insurance policy on the property. A homeowner's policy does *NOT* cover business use of the property. Having converted the property to residential rental real estate makes it business use property now. So you need to update your policy to what is called a Rental Dwelling Policy.
Generally a rental dwelling policy only cover's the structure(s) on the property and also include a minimum of $300,000 of liability coverage. It does *NOT* cover the contents inside the structures unless you *specifically* and *explicitly* pay for content coverage. This is because the contents inside a rental property are usually owned by the tenant, and it's the tenant's responsibility to have a "renters insurance" policy.
So in a nutshell, your standard "homeowner's insurance policy" will not cover rental property since it's not being used for "personal use" purposes as outlined in the policy. If you have a claim that claim will be denied and there's nothing you can do about it. So make sure you contact your insurance agent and update the policy. Also let the agent know if you want to insure the contents within the property that you actually own.
I can't stress enough the importance of this; especially if you have a mortgage on that property.
