How does this deal with different password policies?

[probonopd]

How does this deal with different password policies?

Let's say, site 1 requires that passwords are at least 10 characters and contain at least one special character, and site 2 requires that passwords are no more than 8 characters and have no special characters.

[bkueng]

You can select from different password policies with different length.
But you are correct, some sites indeed have strange requirements for max length and forbidden symbols, that do not make any sense. I typically increase the counter until no such symbol is in there.