One of the greatest problems with passwords is having to remember different passwords for different sites. Some people use password managers, others use the password reset link every time they want to login.
I came up with this idea of remembering passwords and I want to know how secure is it. It consists of one common phrase and a suffix/prefix related to the website. For example, we can take a common phrase (for demonstration purposes only) like
abcd124efg. Then a password for security stackexchange could be (taking the first and last letter of the site name)
The advantage of this is that you get a different password for each website while only having to remember one. Now, since the algorithm is known only to the user, it would be hard to know other passwords if someone has access to one of them.
How secure is this algorithm? Would it be used anytime in the future?