How do I add severance into my contract

As the title states, I’m redoing my contract and want to include severance/notice. At the moment my contract states either side is obligated to give a two weeks notice if care is being terminated. Do I need to go beyond that? Personally I don’t want to set myself up to have to give more than a two weeks notice but also have learned that two weeks severance can be a bit tight. I’m also happy to stick to my contract if that’s the standard. I made this contract when I was 19 or so. So it’s up to be redone with me switching jobs soon. Thanks for any advice!