This is a rant about dumb password policies enforced by some websites or apps. If you see these password rules forced to you, try to stay away if possible.
Can’t use special characters, or use a pre-defined special characters only
Are you storing the password in plaintext that your database will break when have special characters?
Password can’t be longer than X characters
Most probably storing the password in plaintext and their database column is limited to those characters limit.
Password expire every X months, without notice, suddenly can’t login. Reset it and can’t use the last 5 passwords
They store your previous passwords, either encrypted or plaintext.
They don’t need to store previous passwords to prevent reuse, they just need to store the hashes. This is safe.
You wouldn’t know if they hash it or not.
You don’t know if they hash your current password either. Storing the last X passwords is not any reason to infer that they are plain text.
Chances are very good that they’ll hash previous passwords if they hash the current one.