Pressing: Manufacturing may be one of your biggest expenses. There are a few different ways this can go down: If you have a distribution deal, your distributor may pay for manufacturing up front and then recoup the costs from sales.
When a opening takes place (someone retires) then the Marine Corps promotion board looks at the available candidates and their fitness report scores to fill the vacancy. So make sure you have excellent scores and reports. I picked up SSgt (E6) in 10 years. Gunnery Sergeant (E7) may take up to 14 to 16 years.
The strengths of the NYPD are the potential to specialize in may areas (which may be done without making detective) and the relative fairness of the promotion process. The job is what you make of it and going for either Detective or Boss is the way to go for most. However, as it stands, it takes a minimum of 9 years to reach top pay as a Sgt. This is assuming the test is timed right, you pass it and are promoted at five years (the minimum time required in grade to make Sgt.). Those are BIG assumptions. Even if you accomplish this you will essentially make a cops salary until your 9th year. Detectives wait longer.