There is no definitive answer to how long a pre-seed round should last. However, many startups will try to keep their pre-seed round to a shorter timeframe, such as 6-12 months. This is because they want to prove their traction and business model before going out to raise a larger seed round. Additionally, the longer a startup takes to raise money, the more expensive it becomes to keep the business running. therefore, it is generally advisable to try to raise money as quickly as possible in the pre-seed stage.