If you're just starting out it is likely not needed. If you have a rental property, liability coverage should be enough when you are smaller. You can increase the liability coverage on your regular homeowners insurance and also get a supplemental 'umbrella' policy, with can increase the liability limits further. The nice thing with this is the umbrella policy can cover multiple properties as you grow.
Also, lenders will not allow you to close the mortgage loan in an LLC name. It has to be your personal name as it is much harder to foreclose if things go south. After closing you can change the deed over to an LLC but that could trigger the entire mortgage being due if the bank finds out.
All that being said nothing is preventing you from registering as an LLC as it is easier to split up expenses and revenues from your personal accounts. Hopefully this helps!