That depends entirely on how deep you are. If you use Drive to store some personal files, then sure, you move your files to any alternative, install it as needed on your systems, and move on. If you frequently collaborate on Google Docs documents using hangouts and all of your contacts use your @gmail.com email address to communicate with you (whether by email or Hangouts), it gets really messy really fast. And then there are the services which, due to network effects or otherwise, don't have a real alternative yet; notice that this post talks about replacing YouTube with... alternative frontends to YouTube.