If you want to be protected 24h a day then you should consider getting a day/night camera but you'll make sure that it has infrared capabilities if you're looking for high-quality night time coverage. Any regular day/night camera only records good images in low light and no images in total darkness.
The prices of night vision security coverage varies according to everyone's needs. For wider coverage you'll need more cameras and it will cost you a lot while for a simple monitor, a very affordable and easy-to-install wireless system will do the trick.
