> If the site you use the password on gets their database hacked, someone can easily start to brute force passwords. Also, sites getting their databases hacked is not uncommon.

If a sites database is hacked then you can assume their entire site is compromised, in which case whether or not they find out your password is moot because if you use real security and every site has a unique password you risk nothing if they do crack it. If you use the same password for every site cracking is the least of your worries, what if a website is breached and the login system is replaced with a system that stores your password? What if you're phished? What if your computer is stolen and someone just checks your saved passwords? No matter how complex a password is if it's used on multiple websites it's insecure.