On a 2nd home, you can only claim/deduct property taxes and mortgage interest. That's it. But keep in mind that effective with your 2018 taxes, the amount of mortgage interest you can deduct is limited to the first $750K of the outstanding mortgage balance on all homes you own that are not business use. (Rental property is business use). For a non-business use home, the insurance is not deductible and never has been.
On rental property you can deduct mortgage interest (no limit either), property taxes, insurance, cost of repairs and maintenance, and if you the landlord pay the utilities for that rental, that can be deducted against the rental income too.
One thing to note here is that rental income is passive. Therefore rental expenses are also passive. So rental expenses can only be deducted from rental income. Once those expenses get the passive income to zero, that's it. Excess expenses are carried over to the next year. It's very common for the carry overs to increase year to year too. But you will realize those losses in the year you sell the property.
Additionally, on rental property you are required by law to depreciate the property over 27.5 years. Then in the year you sell, that depreciation is recaptured and taxed. For most, the carry over losses will significantly offset that recapture, if not eliminate it entirely.
