• A visa extension application must be submitted no later than on the last day of your legal stay indicated on your visa.
• If the application is submitted after the deadline (during an illegal stay), the initiation of the visa extension procedure is refused.
• If the deadline for the submission of a Schengen visa extension application or a national visa has been met and the application does not have any formal defects – you will receive a stamp in your passport, confirming the submission of the application.
• A visa may be extended only once (excluding cases when it is extended due to a foreigner's stay in hospital)
• The period of your stay based on an extended visa cannot exceed the maximum period allowed for a given type of visa:

365 days – a national visa (excluding a visa with the D/05 symbol, for which the maximum period of stay on the basis of this visa is 180 days within the following 12 months)
90 days of stay within the period of 180 days - Schengen visa

• Documents confirming the ability of having funds to cover the costs of stay or confirming the possibility of obtaining the funds:

a traveller's cheque;
a credit card that can be used by a foreigner on the territory of Poland, together with a certificate on the credit card limit;
a payment card issued by a bank, which can be used by the foreigner on the territory of Poland, together with a balance certificate or an up-to-date bank statement;
a certificate confirming one's funds in a bank or a credit union based in the Republic of Poland in an amount not less than the one specified in Sections 1 and 2, confirmed with a seal and signature of an authorized employee of this bank or credit union issued no later than one month before crossing the border;
the original invitation referred to in Article 16 Section 1 of the Act on Foreigners of 13 June 2003.