And, just to add one more thing to all answers, I'll just talk about latency. Because, it seems that no one wrote here about this.
Having a low client-to-server HTTP latency is critical for making fast-loading, responsive websites.
TCP/IP alone has 3-way handshake (initial connection setup for plain HTTP over TCP requires 3 packets). When SSL/TLS is used, the connection setup is more involved, meaning the latency for new HTTPS connections is unavoidably higher than plaintext HTTP.
The problem with HTTP is that it is not safe. So if you have sensitive data, you need some form of security. When you type something into your web browser beginning with “https”, you are asking your browser to use an encryption layer to protect the traffic. This provides reasonable protection against eavesdroppers, but the problem is that it will be slower. Since we want to encrypt our traffic, there will be some computation involved, which adds to the time. This means that if you don’t design your system correctly, your website will appear sluggish to users.
I have a large content-only site; no login or logout, no usernames,
no email addresses, no secure area, nothing secret on the site, nada.
People just come to the site and go from page to page and look at
If this is the case, I won't use SSL at all. I would like to have my page when you click it that it opens in one second.
That's from user experience. You do as you wish, I just don't put certificates on everything I make. In this particular case, I wouldn't use it at all.