At Schwab, GTC orders remain open for 60 calendar days unless filled or you request that it be canceled before that time.
(GTC) or Open Order - An order to buy or sell that remains in effect until it is either executed or canceled.
Sometimes simply called "GTC", it means an order to buy or sell stock that is good until you cancel it. Brokerages usually set a limit of 30-60 days, at which the GTC expires if not restated.