Once you know all of the approvals and permits you need, applying for them is a very important step in the process. Doing so correctly the first time could save your project a lot of review time.
If applications aren't done correctly, City staff will be forced to collect the right information from you eventually.
If applications are incomplete or unclear, or if the wrong application is submitted, it will take more time for you to complete the application process and receive your approvals for work.
If necessary applications are not submitted and you begin work anyway, your project will be red tagged and stopped, costing you time and money to come into compliance.