A strong password is primarily about length and uniqueness. Reusing a complex password across many services is still risky because one breach can expose multiple accounts.
Prefer unique credentials
Use a different password for every important account. A password manager can generate and store long random values so you do not need to memorize them.
Passphrases can be easier
For passwords you must remember, several unrelated words can create a long passphrase that is easier to type than a short string of symbols.
Add another layer
Enable multi-factor authentication where available, especially for email, financial services and administrator accounts.