Sometime in July 2018, Google Chrome browser will start warning users that any site is not safe to use if it doesn’t have sitewide SSL. It’s also a small ranking factor in Google’s search results. I suspect it will be become a more important factor going forward.
Here is what it will look like:
You will know if a site is SSL enabled when the beginning of the url starts with https:// instead of http://.
I strongly suggest that this be done to ensure no loss of traffic and/or customers.