If you are only changing the cabinets then you can get read to assemble kitchen cabinets and these should be simple enough for you to go about installing on your own. However if you want something a bit more thorough then just ready to assemble kitchen cabinets may not be enough and you might require a contractor to help you with the process.
Using a contractor is a very good idea because they will have knowledge of everything you need to create your dream kitchen. For instance if you decided you want to move the sink then that doesn't just mean delivering the sink parts and installing it – it also means removing the old sink, handling the plumbing, moving the cabinets and more. That's a lot of different skill sets and even just ordering the help from the right people can be a little complicated here. Contractors make this easier by hiring the help on your behalf.