Take a look at ssh-agent. It's bundled with ssh-client and designed to solve this problem.

The quick usage is, create a terminal and run:

eval `ssh-agent`
ssh-add /path/to/your/encrypted/key1
#type in password
ssh-add /path/to/your/encrypted/key2
... 

# all commands in this terminal will use the keys above w/o asking you for a password 
git clone git@githib.com...
git push... 
etc

So, basically you type your credentials once during the life cycle of your terminal.

If you really want to go full power-user, simple run ssh-agent (without the eval) and you'll see it just sets some env-vars, which can be imported into any terminal/shell you have open.

So, if you put some logic in your shells rc file, you can effectively share a single ash-agent between all your shells, meaning you just need to type your password for your keys once when you log into your system... and your now passwordless for any future terminals you create (this is my setup).

Also, if you're interested take a peek at the man pages for ash-agent. It has a few interesting features (ie: adding a password lock for your agent, removing keys from the agent, etc).

I do it.
Every time.

And I keep a wired keyboard for it.