Engaging..
If you have gravity fed system you do not need to look for anything. If you have a pump system located in your home, ensure it re-primes after cleaning runs and like normal.
Septic tanks have different life spans depending on what they are made of.
Plastic tanks are another option and when installed properly, along with timely pump-outs, can last a lifetime. .
If your tank is a deep tank below the footing of your house, there is no need to cover it, you only need to clean it out..
If you have a shallow tank, 3 feet or less, some protection should be provided from the frost.
Septic fields should have some protection for the winter, especially at the distribution box area, as these areas are usually very close to the surface.
The only answer is -YES- Whether a septic tank or holding tank your alarm will give you fair warning before it starts backing up into your house and causing damage. The alarm will give you time to pump out your tank so you can deal with the issue. If you have a submersible pump in your septic tank, you must have an alarm as you will not know if there is a pump issue until you are literally walking on /in water.