There is no time limit for completing the Stellar 1-Step Challenge. Traders have the freedom to take as much time as they need to complete it.

However, traders need to complete 2 minimum trading days to pass the challenge phase. Traders must open a trade in a unique day to make the day count as a trading day. For example, if a trader opens a trade on Monday and another one on Wednesday, the trader's minimum trading day count will be 2 days. 

On the contrary, there is no minimum trading day requirement in the FundedNext Phase of the Stellar 1-Step Model.