Do not let your domain name expire, pay for its consecutive billing period. Do this before the end of the current billing period to ensure the uninterrupted functioning of your domain and related services (e.g. website, e-mail).
Please note that you may renew it at once for 10 years.
You can check the date of the end of a billing period in the WHOIS database.

If you forget to pay for the domain and it enters BLOCKED state, you can still renew it at your registrar. Do this immediately, don't wait until the last day of this state.

Be sure that your contact data, in particular e-mail address, stored in the .pl registry, are up to date.
Information on any changes should be referred to a registrar.

Change a registrar, if the current one does not suit you.

Remember that, as a registrant of a domain name, you have your rights.

Secure you domain name with DNSSEC.